Tests with mocha + chai

Hey Dan!

I though the only missing part of your awesome seed was tests. Here they come!
I choose to use `mocha` + `chai` for awesomeness.

This integration handle both js and coffee written tests. You can test `js` code with `coffee` tests and vice-versa.

Test can be run from:

* mocha cli
* gulp test
* file save (both test and code will trigger)