Add bullet to VRIntro & create Physics layer that initialzies a simple Bullet scene (press key 7).
Add id to SkeletonHand struct.
Add basisc persistent HandRepresentation in physics & create sample scene.
Remove extraneous define
Allow code to still compile if Bullet not present (In such case, layer 7 is empty)
Lower diffuse lighting color
Reset physics on layer select.
Change scene setup, blocks size & also use real object size when rendering.
Remove some compile warnings.
Merge branch 'master' into add-bullet-physics
Add collider for head position & add bounding sphere that bounces bodies back at same speed.
Disable deactivation to fix unexpected freezes.
Add coments & rotation to SkeletonHand.
Add basic-hacked body holding to PhysicsLayer.
Use grabstrength instead of pinch, only select options in front of hand (hard cut off), use lesser strength for grabbing.
Make cube follow hand's rotation.
Merge branch 'master' into add-bullet-physics

Conflicts:
	source/VRIntroLib/PassthroughLayer.cpp
Merge branch 'master' into add-bullet-physics
Decouple Quaternionf from EigenTypes for now, until the Components linkage issue is sorted out
Enlarge head collider sphere. Require higher confidence to grab blocks