[ODE] Rope Simulation

[Pål- Arve Nilsen]

Correct me if I'm wrong, the "power" of the joint ( in this case I'm 
thinking of a ball joint ) depends on the mass of the two objects 
connected by a joint. I assume that the force pulling the objects 
towards each other, if they're pulled apart by an exterior force, is a 
product including the mass of the two objects.

I have gone through some of the ode code, and I haven't located that 
part that does this yes, haven't had time to look at the solveLCD function.

I have experimented with setting the global cfm and erp using ball 
joints, but haven't been able to get the rope stable when there's a 
heavy load in it. Thoo if I increase the size of the segments in the 
rope, it becomes stable.