Convert to Coffeescript

So I sent you a tweet earlier to ask your opinion on this, here's the full result. It ended up significantly cleaner, which is great. In the process I also made the `parameters` argument option, so users don't have to pass an empty object when they don't have any additional params. There's a nice build and publish process in the makefile which will compile to js before pushing to npm, and the npmignore file has been updated to remove any extra stuff, so the final resulting package to npm should be even lighter.

I know this is more or less a massive rewrite, and absolutely no pressure to accept, just wanted to get your feedback here in general! Next steps for me are to update the request module to include methods other than `get`, and update the constructor to also take the OAuth token in addition to the consumer key.