API review

Proposer: Wim Meeussen

I propose to remove this package. The only purpose it serves is to wrap the service call of the pr2_controller_manager into an action interface. This was useful at the time we were working with trex, because trex could not deal with service calls. Now that we're moving over to smach, there is no more reason to keep this action around. Moreover, in the next release of pr2_mechanism, the interface to the controller manager will most likely be action-based.