Merge pull request #3175 from corbt/es6-modules

enable es6 module syntax

Author: James Ide

docs/JavaScriptEnvironment.md

@@ -34,6 +34,7 @@ ES6
 * [Call spread](http://babeljs.io/docs/learn-es2015/#default-rest-spread): `Math.max(...array);`
 * [Classes](http://babeljs.io/docs/learn-es2015/#classes): `class C extends React.Component { render() { return <View />; } }`
 * [Destructuring](http://babeljs.io/docs/learn-es2015/#destructuring): `var {isActive, style} = this.props;`
+* [Modules](http://babeljs.io/docs/learn-es2015/#modules): `import React, { Component } from 'react-native';`
 * [Computed Properties](http://babeljs.io/docs/learn-es2015/#enhanced-object-literals): `var key = 'abc'; var obj = {[key]: 10};`
 * Object Consise Method: `var obj = { method() { return 10; } };`
 * [Object Short Notation](http://babeljs.io/docs/learn-es2015/#enhanced-object-literals): `var name = 'vjeux'; var obj = { name };`