refactoring with abstract classes and interfaces is coming along

python/ur_simple_control/robots/dual_arm_interface.py

...ur_simple_control/robots/force_torque_sensor_interface.py

python/ur_simple_control/robots/heron.py

python/ur_simple_control/robots/implementations/heron.py

python/ur_simple_control/robots/implementations/mir.py

...n/ur_simple_control/robots/implementations/mobile_yumi.py

..._simple_control/robots/implementations/simulated_robot.py

python/ur_simple_control/robots/implementations/ur5e.py

python/ur_simple_control/robots/mobile_base_interface.py

python/ur_simple_control/robots/mobile_yumi.py

python/ur_simple_control/robots/robotmanager_abstract.py

python/ur_simple_control/robots/simulated_robot.py

python/ur_simple_control/robots/single_arm_interface.py

python/ur_simple_control/robots/utils.py