Added Contains for all Vector2d, BoundingCircle and BoundingRectangle's.

- This is to enable a QuadTree implementation
Removed the At property to the collision data.

#23
Modified the collision manager to use a highly optimized quad tree.

- This also involved adding new configuration options to control how the quad tree is created.
- Added an optional parameter to the collision manager monitor function that allows the specification of a static positioned collidable.

#6