Parsing CSS with Parsec

I've used Parsec + Doctest and it was a dream.

> I'd recommend writing a lot of unit tests for your parser. It's easy to play around in the REPL and test things out ...

Doctest feels like a REPL in your source, making it extremely easy to write automated testing. Now I'm wishing for better integration in Sublime Text, so it will tell me if I have an error in the editor, without hitting the terminal.