[ADD] zm_urban_cargo_express

[Rezel]

After looking into detail on this map, I came to the conclusion that it was a very well made map. many of the spots are not cheap, there is always a way to get the Humans if they aren't paying attention, or doing what they are supposed to:

http://www.gamebanana.com/maps/155618

[B1ackOut]

Looks good to me, we always need more good barricade maps.