New System used for Light
MessageReceiver requires HAS-A
New System used for RigidBody. Rework needed

Split PhysicsWorld and Scene.
PhysicsWorld keeps reference at btRigidBody and SceneNodes at once
Additional to previous commit
Corrected relations (HAS-A _ IS-A)
Fixed Bug. Velocities can be set
Parted Scene and World. RigidBody has no use anymore
Renamed class World to PhysicsWorld
Oculus Dist works for 1280x800. StereoCamera does not...