[ODE] Dynamic trimesh's

[Brad]

I destroyed the old trimesh data and created a new one, then attached it 
to the trimesh using dGeomTriMeshSetData(), but I was still getting the 
AABB problems. I looked in the ODE source and saw that the AABB of the 
trimesh geometry was never getting regenerated when a new trimesh data 
was attached. I added a computeAABB() call to dGeomTriMeshSetData() and 
that seems to work. Should that be added in CVS?