PR2

Infrastructure to control the PR2 robot in a hard realtime control loop.

willow_maps is moved in from SVN and contains all the parameters needed for packages in the pr2_apps stack, specifically the pr2_app_manager metapackage.

PR2-specific components that are used in bringing up a robot.

Drivers for the ethercat system and the peripherals on the PR2.

pr2_gripper_sensor package from pr2_object_manipulation.