The launch file aseba_slam_nav_viewer.launch starts a complete SLAM and
navigation system for a Thymio with an Hokuyo mounted on its top.

For this launch file to work, you must first connect the Hokuyo and then
the Thymio, so that the Hokuyo gets /dev/ttyACM0 as device and the
Thymio /dev/ttyACM1.
