Add Brick shape for ContactGeometry

This is a first installment in proper geometry handling for convex meshes that can be used with either compliant or rigid contact. 

- Added convex mesh features to Geo::Box.
- Added penalty force generator for Brick-HalfSpace Contact.
- Added adhoc test ContactBrickTest showing mesh topology and displaying generated forces & force details.
- Misc. contact cleanup.
Could submit to [Journal for the Academic Study of Magic](http://mandrake.uk.net/journal-for-the-academic-study-of-magic/), which covers "all areas of magic, witchcraft, paganism, etc." :smile: