Add support for %Y in Rice

I noticed that your branch didn't have support for %Y in time notation, and later that your support for %y was not exactly future-proof.  I was going to email you about it, but I decided to make the changes myself, and learn a bit about coffeescript, git, and github in the process.  I don't think I screwed anything up too badly; I tested my fork to ensure that it worked properly before submitting the pull request.