Use webpack-merge.

Move html export config to own file.
Delete unnecessary config options.
Use cheap source maps.

Signed-off-by: David Mehren <dmehren1@gmail.com>

webpack.common.js

@@ -10,6 +10,7 @@ var gracefulFs = require('graceful-fs')
 gracefulFs.gracefulify(fs)
 
 module.exports = {
+  name: 'app',
   plugins: [
     new webpack.ProvidePlugin({
       Visibility: 'visibilityjs',