changes to let us use macros to build UR5's. macro creating the base UR5
as per our previous demos is in base_ur5.urdf.xacro; planning_context
now calls the xacro file instead of the urdf.
Robotiq file changes, everything can compile and launch but does not
know all robot links right now and controllers don't work very well.
Also fixed robotiq control so that the CMakeLists doesn't run into
trouble looking for ros_control and ros_controllers.