Wnen expanding the map, if 0 cities are to be created, create 0 cities!
Try again to fix the map expansion bug -- more cleanly.
Prevent addition of more cities than requested when expanding map.
Clean up logic in generate_cities slightly.
City bridges did not have weight limits set correctly.  Cause these to be set correctly in bauer/brueckenbauer.cc.
VERSION: Increment to 11.9003
Merge branch 'jp-devel-fixes' of git://github.com/neroden/simutrans.git into 112.x-private-car-merge