[ODE] Joint stop parameters cause error

[lukasz@datafast.net.au]

I've create a simple two box model, joined at the ends with a hinge. The
boxes can collide with the ground plane, but not with themselves. I've
bound a key to give one of the boxes a push up, and then it comes back to
the ground due to gravity. Everything works ok so far. I've bound a key to
toggle dParamLoStop and dParamHiStop on and off. When I turn the stop
parameters on which constrain the angle of the hinge to around 90 degrees
(+- a fraction of Pi), it works fine. The problem occurs when I turn off
the stop parameters (by setting lo to -dInfinity, and hi to dInfinity).
What happens then is the boxes start falling appart on their own, as if
ERP on the hinge was set to 0. I've tried various combinations of CRM and
ERP from 0 to 1, and this phenomenon occurs regardless.

I don't need to be able to turn off the constraints, as I'll be using them
throught the entire simulation. I thought I'd just raise this issue to the
community and see if anyone has a similar problem.

Lukasz.