- add NetworkGroupNode and recognize groups of nodes with same ip in traceroute outputs
- improve some toString methods
- add tests for group recognition
- add addPort method to NetworkDevice
- fix InputDispatcher for routeTp commands 
- add line breaks and indents to DotWriters
- traceroute process can handle different protocols, ICMP is default (did improve results)
- terminate traceroute after 5 "* * *" responses
- introduce NetworkBlockingNode in order to indicate a termination after 5 "* * *"