Fix firefox (worked in Chrome only) sourcemaps in dev mode.

client/webpack.config.js

@@ -99,9 +99,6 @@ let buildconfig = {
             name: "libs",
             filename: "libs.bundled.js"
         }),
-        new webpack.SourceMapDevToolPlugin({
-            filename: '[name].js.map',
-        }),
         // this plugin allows using the following keys/globals in scripts (w/o req'ing them first)
         // and webpack will automagically require them in the bundle for you
         new webpack.ProvidePlugin({
@@ -115,7 +112,7 @@ let buildconfig = {
     ]
 };
 
-if (process.env.GXY_BUILD_SOURCEMAPS){
+if (process.env.GXY_BUILD_SOURCEMAPS || process.env.NODE_ENV == "development"){
     buildconfig.devtool = 'source-map';
 }