diff --git a/package-lock.json b/package-lock.json
index 5e83268..dd0fe4a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "sd-expression-engine",
-  "version": "0.1.14",
+  "version": "0.1.15",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -3762,7 +3762,7 @@
         },
         "util": {
           "version": "0.10.3",
-          "resolved": "http://registry.npmjs.org/util/-/util-0.10.3.tgz",
+          "resolved": "https://registry.npmjs.org/util/-/util-0.10.3.tgz",
           "integrity": "sha1-evsa/lCAUkZInj23/g7TeTNqwPk=",
           "dev": true,
           "requires": {
@@ -3881,7 +3881,7 @@
         },
         "chalk": {
           "version": "1.1.3",
-          "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
           "dev": true,
           "requires": {
@@ -6964,7 +6964,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -6985,12 +6986,14 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -6998,24 +7001,25 @@
         },
         "chownr": {
           "version": "1.1.1",
-          "bundled": true,
-          "dev": true,
-          "optional": true
+          "bundled": true
         },
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -7053,8 +7057,6 @@
         "fs-minipass": {
           "version": "1.2.5",
           "bundled": true,
-          "dev": true,
-          "optional": true,
           "requires": {
             "minipass": "^2.2.1"
           }
@@ -7132,7 +7134,8 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "ini": {
           "version": "1.3.5",
@@ -7144,6 +7147,7 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -7158,6 +7162,7 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -7165,12 +7170,12 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "minipass": {
           "version": "2.3.5",
           "bundled": true,
-          "dev": true,
           "requires": {
             "safe-buffer": "^5.1.2",
             "yallist": "^3.0.0"
@@ -7179,8 +7184,6 @@
         "minizlib": {
           "version": "1.2.1",
           "bundled": true,
-          "dev": true,
-          "optional": true,
           "requires": {
             "minipass": "^2.2.1"
           }
@@ -7189,6 +7192,7 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -7269,7 +7273,8 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -7281,6 +7286,7 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -7365,8 +7371,7 @@
         },
         "safe-buffer": {
           "version": "5.1.2",
-          "bundled": true,
-          "dev": true
+          "bundled": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -7402,6 +7407,7 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -7421,6 +7427,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -7432,18 +7439,90 @@
           "optional": true
         },
         "tar": {
-          "version": "4.4.8",
-          "bundled": true,
+          "version": "4.4.19",
+          "resolved": "https://registry.npmjs.org/tar/-/tar-4.4.19.tgz",
+          "integrity": "sha512-a20gEsvHnWe0ygBY8JbxoM4w3SJdhc7ZAuxkLqh+nvNQN2IOt0B5lLgM490X5Hl8FF0dl0tOf2ewFYAlIFgzVA==",
           "dev": true,
           "optional": true,
           "requires": {
-            "chownr": "^1.1.1",
-            "fs-minipass": "^1.2.5",
-            "minipass": "^2.3.4",
-            "minizlib": "^1.1.1",
-            "mkdirp": "^0.5.0",
-            "safe-buffer": "^5.1.2",
-            "yallist": "^3.0.2"
+            "chownr": "^1.1.4",
+            "fs-minipass": "^1.2.7",
+            "minipass": "^2.9.0",
+            "minizlib": "^1.3.3",
+            "mkdirp": "^0.5.5",
+            "safe-buffer": "^5.2.1",
+            "yallist": "^3.1.1"
+          },
+          "dependencies": {
+            "chownr": {
+              "version": "1.1.4",
+              "resolved": "https://registry.npmjs.org/chownr/-/chownr-1.1.4.tgz",
+              "integrity": "sha512-jJ0bqzaylmJtVnNgzTeSOs8DPavpbYgEr/b0YL8/2GO3xJEhInFmhKMUnEJQjZumK7KXGFhUy89PrsJWlakBVg==",
+              "dev": true,
+              "optional": true
+            },
+            "fs-minipass": {
+              "version": "1.2.7",
+              "resolved": "https://registry.npmjs.org/fs-minipass/-/fs-minipass-1.2.7.tgz",
+              "integrity": "sha512-GWSSJGFy4e9GUeCcbIkED+bgAoFyj7XF1mV8rma3QW4NIqX9Kyx79N/PF61H5udOV3aY1IaMLs6pGbH71nlCTA==",
+              "dev": true,
+              "optional": true,
+              "requires": {
+                "minipass": "^2.6.0"
+              }
+            },
+            "minimist": {
+              "version": "1.2.5",
+              "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.5.tgz",
+              "integrity": "sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==",
+              "dev": true,
+              "optional": true
+            },
+            "minipass": {
+              "version": "2.9.0",
+              "resolved": "https://registry.npmjs.org/minipass/-/minipass-2.9.0.tgz",
+              "integrity": "sha512-wxfUjg9WebH+CUDX/CdbRlh5SmfZiy/hpkxaRI16Y9W56Pa75sWgd/rvFilSgrauD9NyFymP/+JFV3KwzIsJeg==",
+              "dev": true,
+              "optional": true,
+              "requires": {
+                "safe-buffer": "^5.1.2",
+                "yallist": "^3.0.0"
+              }
+            },
+            "minizlib": {
+              "version": "1.3.3",
+              "resolved": "https://registry.npmjs.org/minizlib/-/minizlib-1.3.3.tgz",
+              "integrity": "sha512-6ZYMOEnmVsdCeTJVE0W9ZD+pVnE8h9Hma/iOwwRDsdQoePpoX56/8B6z3P9VNwppJuBKNRuFDRNRqRWexT9G9Q==",
+              "dev": true,
+              "optional": true,
+              "requires": {
+                "minipass": "^2.9.0"
+              }
+            },
+            "mkdirp": {
+              "version": "0.5.5",
+              "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.5.tgz",
+              "integrity": "sha512-NKmAlESf6jMGym1++R0Ra7wvhV+wFW63FaSOFPwRahvea0gMUcGUhVeAg/0BC0wiv9ih5NYPB1Wn1UEI1/L+xQ==",
+              "dev": true,
+              "optional": true,
+              "requires": {
+                "minimist": "^1.2.5"
+              }
+            },
+            "safe-buffer": {
+              "version": "5.2.1",
+              "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
+              "integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==",
+              "dev": true,
+              "optional": true
+            },
+            "yallist": {
+              "version": "3.1.1",
+              "resolved": "https://registry.npmjs.org/yallist/-/yallist-3.1.1.tgz",
+              "integrity": "sha512-a4UGQaWPH59mOXUYnAG2ewncQS4i4F43Tv3JoAM+s2VDAmS9NsK8GpDMLrCHPksFT7h3K6TOoUNn2pb7RoXx4g==",
+              "dev": true,
+              "optional": true
+            }
           }
         },
         "util-deprecate": {
@@ -7464,12 +7543,12 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.3",
-          "bundled": true,
-          "dev": true
+          "bundled": true
         }
       }
     },
@@ -7788,7 +7867,7 @@
         },
         "load-json-file": {
           "version": "1.1.0",
-          "resolved": "http://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
+          "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
           "integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
           "dev": true,
           "requires": {
@@ -7830,7 +7909,7 @@
         },
         "pify": {
           "version": "2.3.0",
-          "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+          "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
           "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
           "dev": true
         },
@@ -8064,7 +8143,7 @@
         },
         "chalk": {
           "version": "1.1.3",
-          "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
           "dev": true,
           "requires": {
@@ -8086,7 +8165,7 @@
         },
         "kind-of": {
           "version": "1.1.0",
-          "resolved": "http://registry.npmjs.org/kind-of/-/kind-of-1.1.0.tgz",
+          "resolved": "https://registry.npmjs.org/kind-of/-/kind-of-1.1.0.tgz",
           "integrity": "sha1-FAo9LUGjbS78+pN3tiwk+ElaXEQ=",
           "dev": true
         },
@@ -8213,7 +8292,7 @@
         },
         "chalk": {
           "version": "1.1.3",
-          "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
           "dev": true,
           "requires": {
@@ -8493,7 +8572,7 @@
       "dependencies": {
         "commander": {
           "version": "2.9.0",
-          "resolved": "http://registry.npmjs.org/commander/-/commander-2.9.0.tgz",
+          "resolved": "https://registry.npmjs.org/commander/-/commander-2.9.0.tgz",
           "integrity": "sha1-nJkJQXbhIkDLItbFFGCYQA/g99Q=",
           "dev": true,
           "requires": {
@@ -10717,6 +10796,11 @@
         }
       }
     },
+    "mkdirp": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-1.0.4.tgz",
+      "integrity": "sha512-vVqVZQyf3WLx2Shd0qJ9xuvqgAyKPLAiqITEtqW0oIUjzo3PePDd6fW9iFz30ef7Ysp/oiWqbhszeGWW2T6Gzw=="
+    },
     "mkdirp-classic": {
       "version": "0.5.3",
       "resolved": "https://registry.npmjs.org/mkdirp-classic/-/mkdirp-classic-0.5.3.tgz",
@@ -10777,7 +10861,7 @@
         },
         "readable-stream": {
           "version": "1.1.14",
-          "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-1.1.14.tgz",
+          "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-1.1.14.tgz",
           "integrity": "sha1-fPTFTvZI44EwhMY23SB54WbAgdk=",
           "dev": true,
           "requires": {
@@ -10941,17 +11025,24 @@
           }
         },
         "tar": {
-          "version": "4.4.13",
-          "resolved": "https://registry.npmjs.org/tar/-/tar-4.4.13.tgz",
-          "integrity": "sha512-w2VwSrBoHa5BsSyH+KxEqeQBAllHhccyMFVHtGtdMpF4W7IRWfZjFiQceJPChOeTsSDVUpER2T8FA93pr0L+QA==",
-          "requires": {
-            "chownr": "^1.1.1",
-            "fs-minipass": "^1.2.5",
-            "minipass": "^2.8.6",
-            "minizlib": "^1.2.1",
-            "mkdirp": "^0.5.0",
-            "safe-buffer": "^5.1.2",
-            "yallist": "^3.0.3"
+          "version": "4.4.19",
+          "resolved": "https://registry.npmjs.org/tar/-/tar-4.4.19.tgz",
+          "integrity": "sha512-a20gEsvHnWe0ygBY8JbxoM4w3SJdhc7ZAuxkLqh+nvNQN2IOt0B5lLgM490X5Hl8FF0dl0tOf2ewFYAlIFgzVA==",
+          "requires": {
+            "chownr": "^1.1.4",
+            "fs-minipass": "^1.2.7",
+            "minipass": "^2.9.0",
+            "minizlib": "^1.3.3",
+            "mkdirp": "^0.5.5",
+            "safe-buffer": "^5.2.1",
+            "yallist": "^3.1.1"
+          },
+          "dependencies": {
+            "safe-buffer": {
+              "version": "5.2.1",
+              "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
+              "integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ=="
+            }
           }
         },
         "yallist": {
@@ -11677,7 +11768,7 @@
       "dependencies": {
         "minimist": {
           "version": "0.0.10",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-0.0.10.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.10.tgz",
           "integrity": "sha1-3j+YVD2/lggr5IrRoMfNqDYwHc8=",
           "dev": true
         }
@@ -12464,7 +12555,7 @@
     },
     "readable-stream": {
       "version": "2.3.6",
-      "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-2.3.6.tgz",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.6.tgz",
       "integrity": "sha512-tQtKA9WIAhBF3+VLAseyMqZeBjW0AHJoxOtYqSUZNJxauErmLbVm2FW1y+J/YA9dUrAC39ITejlZWhVIwawkKw==",
       "requires": {
         "core-util-is": "~1.0.0",
@@ -14066,7 +14157,7 @@
     },
     "strip-ansi": {
       "version": "3.0.1",
-      "resolved": "http://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
       "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
       "requires": {
         "ansi-regex": "^2.0.0"
@@ -14139,32 +14230,27 @@
       }
     },
     "tar": {
-      "version": "6.0.2",
-      "resolved": "https://registry.npmjs.org/tar/-/tar-6.0.2.tgz",
-      "integrity": "sha512-Glo3jkRtPcvpDlAs/0+hozav78yoXKFr+c4wgw62NNMO3oo4AaJdCo21Uu7lcwr55h39W2XD1LMERc64wtbItg==",
+      "version": "6.1.11",
+      "resolved": "https://registry.npmjs.org/tar/-/tar-6.1.11.tgz",
+      "integrity": "sha512-an/KZQzQUkZCkuoAA64hM92X0Urb6VpRhAFllDzz44U2mcD5scmT3zBc4VgVpkugF580+DQn8eAFSyoQt0tznA==",
       "requires": {
         "chownr": "^2.0.0",
         "fs-minipass": "^2.0.0",
         "minipass": "^3.0.0",
-        "minizlib": "^2.1.0",
+        "minizlib": "^2.1.1",
         "mkdirp": "^1.0.3",
         "yallist": "^4.0.0"
       },
       "dependencies": {
         "minizlib": {
-          "version": "2.1.0",
-          "resolved": "https://registry.npmjs.org/minizlib/-/minizlib-2.1.0.tgz",
-          "integrity": "sha512-EzTZN/fjSvifSX0SlqUERCN39o6T40AMarPbv0MrarSFtIITCBh7bi+dU8nxGFHuqs9jdIAeoYoKuQAAASsPPA==",
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/minizlib/-/minizlib-2.1.2.tgz",
+          "integrity": "sha512-bAxsR8BVfj60DWXHE3u30oHzfl4G7khkSuPW+qvpd7jFRHm7dLxOjUk1EHACJ/hxLY8phGJ0YhYHZo7jil7Qdg==",
           "requires": {
             "minipass": "^3.0.0",
             "yallist": "^4.0.0"
           }
         },
-        "mkdirp": {
-          "version": "1.0.4",
-          "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-1.0.4.tgz",
-          "integrity": "sha512-vVqVZQyf3WLx2Shd0qJ9xuvqgAyKPLAiqITEtqW0oIUjzo3PePDd6fW9iFz30ef7Ysp/oiWqbhszeGWW2T6Gzw=="
-        },
         "yallist": {
           "version": "4.0.0",
           "resolved": "https://registry.npmjs.org/yallist/-/yallist-4.0.0.tgz",
@@ -15301,7 +15387,7 @@
     },
     "wrap-ansi": {
       "version": "2.1.0",
-      "resolved": "http://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
       "integrity": "sha1-2Pw9KE3QV5T+hJc8rs3Rz4JP3YU=",
       "dev": true,
       "requires": {