Implementing React.createElement

[vitkarpov]

Hey Luke,

I'm really into what you're doing here. Helps to dive into React internals and grasp all the stuff more easy, so thank you in the first place :)

So, about the issue. I think it would be convenient to implement React.createElement in a very simplified way, just like you have in comments within renderDOM.jsx now: transpile its calls to objects. Seems demystifying React.createElement is useful too.

I can make a pull if you think it's a good idea. What do you think?