Strip comments from the production build (#5)

* Strip comments from the production build

* Add screw_ie8 options to UglifyJsPlugin

webpack.config.prod.js

@@ -91,6 +91,18 @@ module.exports = {
     }),
     new webpack.DefinePlugin({ 'process.env.NODE_ENV': '"production"' }),
     new webpack.optimize.OccurrenceOrderPlugin(),
-    new webpack.optimize.UglifyJsPlugin({ compressor: { warnings: false } })
+    new webpack.optimize.UglifyJsPlugin({
+      compressor: {
+        screw_ie8: true,
+        warnings: false
+      },
+      mangle: {
+        screw_ie8: true
+      },
+      output: {
+        comments: false,
+        screw_ie8: true
+      }
+    })
   ]
 };