Rewrite frontend with coffeescript

This isn't entirely ready to merge, but it's close.

@jdiez17 please check out the backend changes and make any adjustments you see fit. Notable problems are that mediacrush.js isn't being preprocessed and coffeescript files can't have unicode characters in them.

The frontend work is nearly done, I have to finish implementing something in api.coffee and I have to make minor changes to view.coffee. I would like to rewrite the media player JS with coffeescript, but I'm going to do that later, when I do the full-fledged media player overhaul.