Test coverage

[SBoudrias]

It is actually quite hard to provide easy test coverage via Backbone-Boilerplate tool set.

Spawning the server actually prevent Karma coverage tools from instrumenting the files. I'm not sure what we could do about this, but I guess we'll need to provide our own instrumented files via the server task.

I've create a basic karma-coverage setup on my BBB fork, right now it cover all the files (even test framework and stuff as a proof it's working), but in the coverage report we see the files served are completely ignored (which make sense).