in this test we test the general rules of traffic flow in the round about.
Cars entering the roundabout yeild to cars already in the roundabout.
Cars leave at their appropriate exit.

You might notice that a car entering from an entrence cell is a 9 but becomes 8. This is due to numofhopsleft = 0 and so the extNumberPort changes to 8
to indicate that the car will leave the system in the mini roundabout. This is old behaviour and has been replaced with decrementing
numofhopsleft by 1 when the car info is passed from one mini roundabout to another.