Spies, Mocks and stub for our Unit test

Created by: Johann-S

We should add a libs which will allow us to use Spies, Mocks and Stubs, I thought about Sinon : http://sinonjs.org/

It would be easier for us to test our plugins

Because, I work on improving our code coverage but it's very difficult to test everything with QUnit which do not provide enough tools for that...

/CC @XhmikosR, @bardiharborow