Initial implementation and spec tests.

This just means it will built using 1.9.3 (this is in the Gemfile, not in the gemspec). I'm using 1.9.3 because I don't really need any features from 2+, and I might as well leave it compatible with 1.9.3 if it isn't costing me anything. Nuts to 1.8.7 though, that's super ancient (and I like to be able to use the new hash syntax) :).