React.renderComponent -> React.render

Also rename all the associated render methods and adds deprecation notices.

- [ ] Figure out if this will break Om (or more specifically closure compiler advanced, I think yes because of strings vs keys, maybe use `keyOf`)
- [ ] Update method names in `ReactMount`, `ReactServerRendering`
- [ ] Decide what to do about `unmountComponentAtNode`

I think we should make sure we do any other API changes in the same release cycle as much as possible.
* `createElement/Node/Whatever`?
* remove `Component` from lifecycle methods?

cc @sebmarkbage
maybe warn only once per method?