[ODE] ODE joint internals

[Jon Watte]

> ** I need to be able to switch out one of the Bodys connected to a 
> Joint while leaving the other joint parameters (such as anchor 
> and axis positions, relative rotations, etc.) unchanged as viewed 
> in global coordinates, even though the new Body's position and 
> orientation may be different. **

I suggest tracking your configuration data separately from ODE. When the configuration changes, nuke the old ODE representation of the robot, and call a function that re-generates the ODE representation of the robot from scratch. This is much easier to implement, debug, and make robust. If you need to preserve joint angles, velocities, etc, then give each of your piece joints an internal ID, extract parameters-per-ID before nuking, and re-apply whatever IDs are re-used after re-construction.

Cheers,

			/ h+