[Webpack] Change images to not use relative path. (#423)

* Change webpack config to not use relative path for images.

Resolves #421.

* Move popup images to popup/images.

* Move images to popup/images.

webpack.common.js

@@ -48,11 +48,13 @@ module.exports = {
             },
             {
                 test: /\.(jpe?g|png|gif|svg)$/i,
+                exclude: /.*(fontawesome-webfont|glyphicons-halflings-regular)\.svg/,
                 use: [{
                     loader: 'file-loader',
                     options: {
-                        name: '[name].[ext]',
-                        useRelativePath: true
+                        name: '[name].[hash].[ext]',
+                        outputPath: 'popup/images/',
+                        publicPath: '/'
                     }
                 }]
             }