Merge pull request #657 from clark800/fix-polyfill

Fix babel-polyfill require

src/api.js

@@ -9,7 +9,7 @@
 // In node.js env, polyfill might be already loaded (from any npm package),
 // that's why we do this check.
 if (!global._babelPolyfill) {
-  require('babel-core/polyfill');
+  require('babel-polyfill');
 }
 
 const _ = require('lodash');