Merge branch 'bgrozev-restrict-eslint-versions'

package.json

     "babel-loader": "*",
     "babel-polyfill": "*",
     "babel-preset-es2015": "*",
-    "eslint": "*",
+    "eslint": ">=3",
     "jshint": "^2.8.0",
     "precommit-hook": "^3.0.0",
     "string-replace-loader": "*",