Avoid webpack to insert setImmediate

Author: ai

src/util/index.js src/util.jssrc/util/index.js renamed to src/util.js

@@ -1,4 +1,6 @@
 export function deferAction(action) {
+  // Hidding setImmediate from Webpack to avoid inserting polyfill
+  const setImmediate = window.setImmediate;
   if (typeof setImmediate !== 'undefined') {
     setImmediate(action);
   } else {