Adapted human_aware_navigation and gaze_at_pose

human_aware_navigation:
* Now takes a move_base/MoveBaseAction and sends a navigation while reconfiguring the speed according to the distance of the closest human. Should enable it to be used in topological navigation.

gaze_at_pose:
* Bugfix for pose calculation when looking to the back.
* remove reset of head pose when cancelled to not have it spin around all the time
* fixe tf transform lookup warining