Updates for UniversalRobot on raw3-1

This PR allows to use the universal/ur_driver as it is in the official repository. 
By remapping the parameter, no hacks (i.e. global namespace) in driver.py are required anymore.
This PR is the reason why ros-industrial/universal_robot/pull/46 was closed.
It is not depending on the other PRs 43, 44, 45!