refactor(fromJson): always use native JSON.parse

This breaks IE7 for which you can use polyfill:

https://github.com/douglascrockford/JSON-js

<!--[if lt IE 8]>
<script src="json2.min.js"></script>
<![endif]-->

or

http://bestiejs.github.com/json3/

<!--[if lt IE 8]>
<script src="json3.min.js"></script>
<![endif]-->