[ODE] trimesh and capsules bug fix - swapping g1 and g2 in returning contacts

[Jaroslav Sinecky]

There was another old mystery with trimesh and capsules. I always had to 
swap the contact normal and didn't know why if it obviously worked in 
ode test and for other users too. Today finally I sorted that out: the 
g1 and g2 fields in geom struct were swapped when returned from 
trimesh-capsule collision. Depending on whether you used or not this 
information for some further processing and contact joint creation, it 
appeared as a bug or not.

It's fixed and checked-in svn trunk. So if some had to swap the normal 
also (I remember someone commenting  that some time ago), remember to 
swap back now.

Jaroslav