Fixed 'artifact' in PhysicistGameScreen, it was still using 'IPhysicistRegistration' and had a local list of actors.
Merge pull request #39 from chfeltman/bugs

Fixed 'artifact' in PhysicistGameScreen
Addition of DebugView activated by pressing F1
added full support for world rotation
added patch to offset issues and added a correct CenteredPosition to the Actor