Sync'd speed zones

Allow speed zones to be removed by everyone not just creator, this way if someone leaves scene or primary has to leave area for any reason, another unit can cancel out the zone.

Also, allow multi zones.

EX: in the picture im using the bigger speed zone to make traffic slow to 15mph on the highway while going past the smaller 0mph zone. Helps when dealing with highway traffic and an accident that happens just off of it.