Component rendering support

This adds support to render components inline with `h(component)`. This makes way for supporting React `v0.12` by allowing us to call `React.createElement(component)` for the user. [More information](https://gist.github.com/sebmarkbage/ae327f2eda03bf165261).

I've also extended the React api onto `h` so that the React library no longer needs to be required in each file in addition to `h`. Thoughts?

[New documentation here](https://github.com/mlmorg/react-hyperscript/blob/55aee37474d798e8ff2c6ad3037ed33b8a3f4322/README.md)

cc @Raynos @malandrew @ross- @lxe