fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:mime:20170907
- https://snyk.io/vuln/npm:tunnel-agent:20170305

package.json

@@ -21,18 +21,18 @@
         "nunjucks-filter": "1.0.0",
         "i18n": "0.5.0",
         "semver": "5.0.1",
-        "npmi": "0.1.1",
+        "npmi": "2.0.1",
         "cheerio": "0.19.0",
         "gitbook-plugin-livereload": "0.0.1",
         "chokidar": "~1.0.5",
-        "send": "0.2.0",
+        "send": "0.16.0",
         "tiny-lr": "0.2.1",
         "tmp": "0.0.24",
         "crc": "3.2.1",
         "bash-color": "0.0.3",
         "urijs": "1.17.0",
-        "request": "2.51.0",
-        "npm": "2.4.1",
+        "request": "2.81.0",
+        "npm": "3.0.0",
         "dom-serializer": "0.1.0",
         "spawn-cmd": "0.0.2",
         "escape-string-regexp": "1.0.3",