chore(package): update webpack to version 2.4.1

Closes #288

https://greenkeeper.io/

package.json

@@ -66,7 +66,7 @@
     "svg-to-image": "1.1.3",
     "svg-url-loader": "2.0.2",
     "travis-after-all": "^1.4.4",
-    "webpack": "2.3.2",
+    "webpack": "2.4.1",
     "webpack-dev-server": "^2.4.1",
     "xhr": "2.4.0"
   }