Added button code

This is the version of the code I've been using for the past two years.  I just tried it ruby 2.0.0-p247, ruby 1.8.7-p358 (the stock ruby on my Mac), and ruby ruby-1.9.1-p376.

Parsing ri output is hard because it changes.  I can find places in different versions where the parse does not work but it works most of the time.  When it does, it really nice.  When it doesn't, you have to revert back to typing in your request.

I hope you find it useful.