[ODE] FPS Player again

[David Walters]

> afaik most fps use collision boxes for the player. Modern fps use
> several boxes which may collide. I am not sure, how to prevent the boxes
> from colliding in ode.

If you tag a geom with some user data which says if it's a hit box or
not, you can use that to simply _not_ create contact joints for
collsions involving those geoms. Remember all dCollide does is report
collsions, it's the contact joints that actually affect change in the
world - and it's up to your code whether they get created or not!

Regards,
Dave.