Fully integrate composer

This PR makes it so Kohana modules must be installed using composer instead of using git submodules. 

Modules with the composer type of "kohana-module" are forced to be installed into the standard vendor directory.
The unittest bootstrap needs to be updated with quite a few changes.

Testing is in a real mess at the moment. I really wish Koharness would implement the functionality of the unittest module, then we'd only need one package for testing a module in isolation. It's going to get complicated if we have to keep the bootstraps up to date of both Koharness and the unittest module.