Check CoffeeScript using CoffeeLint

At my company we have quite a lot of CoffeeScript code, and I would love for Hound to be able to check CoffeeScript code too, not just Ruby. The current implementation only checks four rules, however if more rules are added to CoffeeLint they should be fairly straight-forward to add to Hound.
My thinking on https://github.com/thoughtbot/hound/pull/349 was to re-use the `Violation` value object for all style guide types. Have its interface be a filename, line number, and messages.