Added a new sphere intersection test.

A new sphere intersection test for the spheres surrounding our other volumes which is cheaper since it doesn't calculate intersection data.
Added 2 new collision functions.
works.
still works. redid previous work.
New assets
Implemented air control.

Needs tweaking.
Air control messing up fall speed fixed.

We still lose some velocity if we stop steering in air which needs to be fixed.
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