restructuring

This removes scitos_launch, adds a PTU driver, renames the package "scitos_driver" to "scitos_mira" and provides launch files that are linked into scitos_robot/scitos_bringup.

The repository is then renamed "scitos_mira" => "scitos_drivers" - I don't know if the pull request will achieve this so @hawesie or @marc-hanheide should rename the repo manually if not..