There's currently no universal way to give objects an angular velocity. There is addTorque, but it only works on PhysX objects.
So you have to do a loop every frame and rotate the object manually.
Having such command would be very useful for having true 6 DoF motion using scripts.
obj setAngularVelocity [wx, wy, wz];
the units are rad/s
and a getter command:
I think it makes the most sense if the reference coordinate was the model itself. But you can make world and model variants if you think it's better.