I actually saw your library, it's super cool - it's currently pretty much the top result for "Rap Genius API", apart from the tweet I refer to (https://twitter.com/RapGenius/statuses/245057326321655808).
As I've said in other comments, I'd love RG to have a public API, but I can see why they don't.
It'd be cool to compare notes on parsing Rap Genius. Drop me an email if you have a moment, me@timrogers.co.uk.