extending prototype functions in order to fix hot loader

[bobbyrenwick]

This also removes the setting up of the initial this.state._radiumStyleState because there's no way to reconcile the differences between ES6 classes and React.createClass without creating a wrapping constructor that kills hot loading. It also removes the tests for that behaviour because it doesn't actually seem to negatively affect the behaviour.

You can see that this branch works with hot loader by cloning my fork of react-hot-boilerplate - https://github.com/bobbyrenwick/react-hot-boilerplate/tree/test-radium-hoc.

The only thing I'm not too sure about is that I've deleted some Flow annotations and I'm not sure what sort of effects that will have as I haven't had much time to play around with it! @ianobermiller is there anything Flow related that needs to be done?

Fixes #219

[bobbyrenwick]

So I've been testing this out on our app today and it seems that there are some issues with this. I will let you know more once I've done some more testing.

[bobbyrenwick]

So the issue was caused by removing, _radiumStyleState from the initialState while using PureRenderMixin. For example, on a hover, in shallowEqual we end up comparing a state of null (the initial state) to a state of {"_radiumStyleStyle": {...etc}} and get cannot read property hasOwnProperty of null

[bobbyrenwick]

Closing in favour of #255 because that doesn't have the same issues with PureRenderMixin and no initial state being set.