Who ordered some 3D collision?

- Added math functions for rounding to multiples of a specific number
- Replaced IWorldData with World, which is an abstract class that
manages, you guessed it, the world.
- Added gravity to a 3D world
- Added 3D collision to the height map world.
- Fixed height map 3d terrain generation.
- Inversed the camera's position values. They now logically make sense,
and match up with a real graph.
- Added function to generate height map terrain from sound files (i.e.
reads loudness)
- Tried to set up bounding boxes, but failed miserably. Will try again,
next time, on objects that DO NOT HAVE CURVED EDGES.
- Added noclip, a way of turning off collision detection.
- Height map worlds now render as a display list.