WurfelEngine needs extensive unit testing.

[galegofer]

WurfelEngineSDK has some new features recently and it tends to incorporate them often, but given that, is a priority to make some housekeep and try to create a good unit test suit to ensure that we are not breaking anything with every new addition.

[BSVogler]

I added support for headless rendering recently so that the unit tests can run without the application window opening every time. I'm all for this.