Added serial port as parameter to launch files
	modified:   create/mobile_base.launch.xml
	modified:   kobuki/mobile_base.launch.xml
	modified:   mobile_base.launch.xml
	modified:   roomba/mobile_base.launch.xml
	modified:   ../minimal.launch

Committer: mayrjohannes <joh.mayr@jku.at>
Author: mayrjohannes <joh.mayr@jku.at>