First pass at an octree for  physic intersection tests.
Fix tests.
Clean up graphics state.
Handle movable and immovable bodies separately.
Merge remote-tracking branch 'origin/master' into Air_control
Stabilized the physics a bit.
GUI overhaul.
Merge remote-tracking branch 'origin/master' into launcher_tweakings
Added icon as resource.
Updated gitignore.
Fix error in cleanup that removed time diffs.
Small fix.
Merge remote-tracking branch 'origin/master' into Air_control

Conflicts:
	Physics/Source/Physics.cpp
GUI changes. Added sound.
Merge remote-tracking branch 'origin/master' into launcher_tweakings
Can't get enough of that launch button...
Merge remote-tracking branch 'origin/master' into Air_control