[ODE] How to use the rotation matrix returned by dGeomGetRotation

[Geoff Carlton]

I skip the entire matrix interface and go instead to the quaternion one, 
since the format is extremely simple and universal (No 3x4 worries 
here!).  Once you have a quat, there are DX functions to convert it to a 
proper DX matrix, or you could just use it directly if you wish to 
transform points to the object's space.

The only gotcha is that ODE has quats as {w,x,y,z} as opposed to the 
expected {x,y,z,w}, so you should swap the elements around.

Geoff