added v2 & v3 control from the kinetic branch.
Also renamed 'elfin_drivers.yaml to elfin_drivers_example.yaml' to improve uniformity with the kinetic branch.
Sorry, this pull request we need to close. Because that we havn't produced the robot with controller_v1 & v2. Now the controller is the controller_v3 before.
added v2 & v3 control from the kinetic branch. Also renamed 'elfin_drivers.yaml to elfin_drivers_example.yaml' to improve uniformity with the kinetic branch.