Add Brick shape for ContactGeometry.
- 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.
Fix gcc/clang compile problem.
Merge pull request #218 from simbody/addContactBrick

Add Brick shape for ContactGeometry