- add seamless switching between cartesian control and joint controller.
- add head control... (target marker, or possibly drag handle.)
- Control to send goals to nav stack.
- Ability to reset head target...
- Individual joint control

MAKE THE ARM MOVE:
  - draw mesh instead of points when object model is known
  - at least figure out why the head action times out
  - model_object should subscribe only when active (and the filter should be idle when not subscribed-to)
