Trafficmodel: Started the impl. of VehicleMaster

For inserting GPS-created vehicles on the right time, a class for
managing the vehciles, which will be inserted. This class is called
GPSVehicleMaster. This class inserts the vehicles into the map, when
the time is right. This class uses a custom Queueimplementation, which
stores the vehicles sorted by their starttime. By adding a vehicle it
is automatically inserted on the right place within the queue. The
only way to remove an vehicle is by removing the first vehicle in the
queue.
Merge branch 'trafficmodel_team1' of github.com:VanetSim/VanetSim into trafficmodel_team1