Refactor look mvc

Refactors LookFragment and LookAdapter into a MVC-Model, similar to that of Sounds.
A LookController handling the logic as well as a LookBaseAdapter (will be needed for backpack) was introduced.

Commits squashed and rebased to master.

Ongoing testrun:
https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/597