Roomba support

I have been trying to use the new groovy turtlebot packages with iRobot Roomba recently and found out that some XML files are missing in order to get the minimal.launch to run. For now I have simply copied the create files and renamed them appropriately and this works (with some adjustment to other packages in other repositories ... I will request merge there as well). I think this is the cleanest way to enable Roomba support that already exists in the python driver and I hope it will be accepted as Roomba support is very important for European turtlebot users.