Adding a Vanilla CoffeeScript example

I was looking for a simple TodoMVC version of CoffeeScript and was surprised to see one didn’t yet exist. I noted in the App Spec that:

> Apps should be written without any preprocessors (Sass/CoffeeScript/..) to reach the largest audience.

However I see there's a vanilla Dart example and some GWT and also CoffeeScript + xyz frameworks, so I'm wondering if there scope for adding a vanilla CoffeeScript example? In any case I thought I’d create and
contribute it back since it was a good opportunity for me to learn a little bit of CoffeeScript and have a comparison against JavaScript.

The coffee files are pretty much literal one to one mappings of the original Vanilla js files.

I checked in the compiled .js files too so the example can be run without having to compile it.