[Tutorials] Fix argv in python launcher.
[Tutorials] Fix argv in python launcher.

In tutorials/launcher.py, other tutorials are launched. It, however,
needs a launch argument, but this argument confuses tutorials that also
depend on sys.argv. Therefore, the first argument of the launcher is
removed now before the actual tutorials are launched.

root-mirror/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,olifre/root,root-mirror/root,olifre/root,karies/root,olifre/root,karies/root,olifre/root,karies/root,olifre/root,olifre/root,karies/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root