Tweak KIF extension to work with Quick

See http://stackoverflow.com/questions/28209769/kif-and-quick-nimble

Author: mokagio

BenchKIFSwift/KIF+SwiftExtension.swift

@@ -1,23 +1,26 @@
 import Quick
 
-extension QuickSpec {
+extension QuickSpec: KIFTestActorDelegate {
 
     func tester(_ file : String = __FILE__, _ line : Int = __LINE__) -> KIFUITestActor {
-        return KIFUITestActor(inFile: file, atLine: line, delegate: self)
+        var t = KIFUITestActor(inFile: file, atLine: line, delegate: self)
+        return t!
     }
 
     func system(_ file : String = __FILE__, _ line : Int = __LINE__) -> KIFSystemTestActor {
         return KIFSystemTestActor(inFile: file, atLine: line, delegate: self)
     }
-}
 
-extension KIFTestActor {
+    // MARK: - KIFTestActorDelegate
 
-    func tester(_ file : String = __FILE__, _ line : Int = __LINE__) -> KIFUITestActor {
-        return KIFUITestActor(inFile: file, atLine: line, delegate: self)
+    override public func failWithException(exception: NSException!, stopTest stop: Bool) {
+        if let userInfo = exception.userInfo {
+            XCTFail(exception.description,
+                file: userInfo["SenTestFilenameKey"] as! String,
+                line: userInfo["SenTestLineNumberKey"] as! UInt)
+        } else {
+            XCTFail(exception.description)
+        }
     }
 
-    func system(_ file : String = __FILE__, _ line : Int = __LINE__) -> KIFSystemTestActor {
-        return KIFSystemTestActor(inFile: file, atLine: line, delegate: self)
-    }
 }