[ODE] Integrated alternate OPCODE trimesh-trimesh collider.

[David Walters]

Hi, just a quick message to say that I've integrated the alternate
trimesh-trimesh collider written by Francisco León (author of
GIMPACT).

To use it, currently, get the latest SVN revision, add the new file to
the project (Jason, can you rebuild the projects please?) and add the
following line to config.h

#define dTRIMESH_OPCODE_USE_NEW_TRIMESH_TRIMESH_COLLIDER 1


Known issues:

* Doesn't compile in dDouble mode
* Missing from project
* Unknown problems / limits? (which is partly why I added it)

Hopefully the remaining problems can be ironed out, but from my own
tests - my engine simulated dropping a cieling fan onto a mesh floor.
In the classic version the fan wobbled about on the floor and looked
very odd, with this new collider it stopped dead!

I see this as a good addition because for me GIMPACT doesn't work too
well for capsule collisions - but with just this aspect (mesh-mesh)
improved in OPCODE I think that ODE users now have a great selection
of mesh solutions!

Regards,
David Walters