Plucking some of the minor changes off my pbd branch to reduce its size. Summarization:
- Fixed/added some comments here and there.
- LevelSetModel extends AbstractDynamicalModel. It can't actually reset so it need only extend AbstractDynamicalModel. Also LevelSetState was removed because it was just an empty class.
- Adds a SurfaceMeshToCapsuleCD test case that is disabled. This is one case not handled yet there.
- Couple of example updates.