chore(package): update webpack to version 1.12.15

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -34,7 +34,7 @@
     "rimraf": "^2.5.2",
     "tslint": "^3.3.0",
     "tslint-loader": "^2.1.0",
-    "webpack": "^1.12.14",
+    "webpack": "^1.12.15",
     "webpack-dev-middleware": "^1.5.1",
     "webpack-hot-middleware": "^2.6.4"
   },