Summary:
I don't know the reasons, why the templates are written with the `react.createClass`method. Today I see lot's of examples using the **ES6 way**. In my own projects I'm using this way, too.
I removed `use strict`, since *Module code is always strict mode code*, according to the [spec](http://www.ecma-international.org/ecma-262/6.0/#sec-strict-mode-code).
Maybe we should **discuss** the usage of ES6 in the templates.
Closes https://github.com/facebook/react-native/pull/4891
Reviewed By: svcscm
Differential Revision: D2789493
Pulled By: androidtrunkagent
fb-gh-sync-id: 90e70f787017c61dc64cbc9f0beb02331fa749ec
bde2f30474