Merge: Geometry fix

Merge: Geometry fix

There was a big mistake in the boxes API where you would get the bottom of a line when calling for it's top and get the top when you were calling for the bottom xD, so fixed it.
There also was a bug with the usage of the Numerics in the quadtree API.
Also implemented a to_s for quadtree, but not sure if it needs to stay here.

Pull-Request: #1534
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Jean Privat <jean@pryen.org>