chore(package): update webpack to version 2.4.0

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -48,7 +48,7 @@
     "tslint-loader": "3.5.2",
     "typedoc": "0.5.10",
     "typescript": "2.2.2",
-    "webpack": "2.3.3"
+    "webpack": "2.4.0"
   },
   "scripts": {
     "test": "karma start karma.conf.js",