minor scene redef
adding more vector utils from Sven implementation
- updated libpedsim to version 2.3 (including patch fixes by Sven)
- necessary refactor due to the update
- birth and death waypoins need to be reworked
additional needed changes with the update
Merge branch 'devel'
Merge branch 'master' of github.com:srl-freiburg/pedsim_ros