Rename Packet to Serialize and redesign it a bit, so now it provides static functions and is not inherited by classes using it.
Update Makefiles.
Update Neighbourhood::Neighbour due to changes in Serializer.
Update test for Serializer.
Update Makefiles.
Rework Neighbourhood constructor.
Add new settings related to multicast communication.
Update Application to use Neighbourhood and Preferences.
Make Neighbourhood announce_present() public and add skeleton for Neighbourhood:announce_leaving().
Improve one of constructors to avoid bad allocations.