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.
Maybe for minor versions, but I think (especially since this is what developers will be expecting) major versions of modules and core should match. EVven if a module doesn't need changes we should tag a 3.4 to make clear it's a supported combination.

in any case kohana/core needs a 3.4 requirement as the bootstrap etc here isn't compatible with 3.3