Adding bounding boxes to the entity class.

Bounding boxes have an offset from Location as determined by the location
of the rectangle the property is set to... (Wow... that was confusing)
Basically, to set a up a bounding box, make a rectangle with the correct
width, height, and offset from the sprite's top left corner.
Merge branch 'master' of github.com:Bacon41/PantheonPrototype

Conflicts:
	PantheonPrototype/PantheonPrototype/Level.cs