Cameras work!

Still some things to fix, like hard-coding squares as the type of
shape. As of yet, there's no way to grab a generic type from the
entity. Wouldn't be hard, I guess just if the initial dictionary lookup
fails, check all the values and see if they inherit the type. Shouldn't
really cause that much of a performance issue. Um, eventually cameras
will be their own entities that may or may not attach to other entities
to follow them around. This would be ideal for networking so that a
player can just hop to another camera view or whatever.