Initial version of beautifying code editors

Here's the initial version of the code beautifier. Beautifies HTML, CSS, & JS - but none of their preprocessor cousins. ( From issue #341 )

It functions, but lacks two important features:

1. **Hot-keys** - I'm probably just being stupid as to why it doesn't work
2. **Beautify settings** - Wasn't sure how you wanted to store them with the rest of the settings and how to display that to people

Should probably also minify the beautifier files.

I tried to copy tern's implementation as much as possible and keep code style conventions.

I'm gonna keep working on (1) but I think (2) might be an implementation detail you guys will want to handle.
This doesn't quite feel right, but if you had trouble getting the binding working then there's something slightly bigger that's an issue.