Add docs badge to README

I just added the badge you requested to your README: ![Inline docs](http://inch-pages.github.io/github/avdi/naught.png)

Your status page for this project is http://inch-pages.github.io/github/avdi/naught

Thanks for giving this a shot!

P.S. Naught seems really cool. I only knew this "blackhole" approach by flori: http://rubylution.ping.de/articles/2006/05/03/null-object-pattern
P.P.S. I really like your "contribution guidelines" :neckbeard: