[kth] Created a KTH simulator environment

This pull request adds

* The sixth floor of our building as a blender file, `data/floorsix.blend`
* A script that creates the environment, `floorsix.py`
* A launch file that starts the script and the Scitos stuff needed, `launch/kth_floorsix.launch`
* A map of the floor built with gmapping, `maps/map.yaml`

Tested on my machine, will add furniture and stairs to the blend file when I have time.