make controllers more defensive

include/ccf/controller/MoveItRobotArmController.h

src/ccf/controller/MoveItRobotArmController.cpp

src/ccf/controller/RobotArmController.cpp

src/dummy_cgv_controller.cpp

src/dummy_rag_controller_a.cpp

src/dummy_rag_controller_b.cpp

src/moveit_cgv_controller.cpp