Add Box2d. TODO: implement in engine
Added Box2D support.

Vectors can now be converted from and to the b2Vec2 vector using Vector2.
More changes which lead to prepair for Box2D implementation.

-Camera is a singleton.
-Added interfaces IComponent and IMovableComponent.
-Removed camera variables.
GameComponent has been redesigned and reimplemented.

- GameComponent now implements IMovableComponent.
- ScreenComponent and it's subclasses have been removed.
- MovableComponent has been removed.
- PhysicsComponent hasn't been removed and will be redesigned.
PhysicsComponent replaced to whojooEngine.components (from whojooEngine.physics)
HuDComponent added and name changes to screens.
Screens have their own componentlist and 2 basic physic shapes added.
Preperations for removing components from Game
Removed component lists from Game
Box2D fully implemented