the config script now finds own IP automatically

pps_ws/src/d_fall_pps/launch/Config.sh

 export ROS_MASTER_URI=http://teacher:11311
-export ROS_IP=10.42.0.33
+export ROS_IP=hostname -I | awk '{print $1;}'
 export ROS_HOSTNAME=student$(cat /etc/StudentID)
 export ROS_NAMESPACE=$(cat /etc/StudentID)