Restructured dirs in preparation for refactor

* Deleted old flight, we don't need it anymore.
Decoupled flight physics from flight controller

Physics operations are now done in a separate class, reflecting a more
model and (view)controller-like design pattern
Fixing metadata problems on master branch

This is a problem that comes about from separating branches by Unity scenes.
Since unity scenes are Un-mergable by git alone, it's nice to keep scene-based
data separate. However, this can cause problems when unity detects that non-scene
data, like scripts, *suddenly* change between branches (which it detects via
metadata files).