Bail for production builds

This ensures errors are not tolerated.
Otherwise, Webpack just builds an empty bundle.

Author: gaearon

config/webpack.config.prod.js

@@ -17,6 +17,7 @@ var isInNodeModules = 'node_modules' ===
 var relative = isInNodeModules ? '../../..' : '..';
 
 module.exports = {
+  bail: true,
   devtool: 'source-map',
   entry: './src/index.js',
   output: {

scripts/build.js

@@ -21,7 +21,8 @@ rimrafSync(relative + '/build');
 
 webpack(config).run(function(err, stats) {
   if (err) {
-    console.error(err);
+    console.error('Failed to create a production build. Reason:');
+    console.error(err.message);
     process.exit(1);
   }