CoffeeScript source maps!

- Moved `.coffee` files into `./lib` (so the `.map` files can find them)
- Added `coffee-script` v1.6.1 as a local npm dependancy
- Updated `Cakefile` tasks to generate source maps
- Recompiled all `.js` files with source maps

All tests are passing, and source maps work great in the Chrome dev tools. :ghost: