Merge pull request #14 from Sungdooyoo/master

fixed out of dated dependency

Author: hemanth

package.json

@@ -13,7 +13,7 @@
     "babel-preset-es2015": "^6.18.0",
     "copy-webpack-plugin": "^4.0.1",
     "css-loader": "^0.26.1",
-    "extract-text-webpack-plugin": "beta",
+    "extract-text-webpack-plugin": "^2.1.0",
     "html-webpack-plugin": "^2.24.1",
     "image-webpack-loader": "^3.0.0",
     "node-sass": "^3.13.0",