implement missing bridge lifting animation for subtraveling sea unit (migrated from trac, id 46 )
Original report is from Tue Sep 15 11:18:01 2009 by user: Obsecraere
Original asignee for this issue is user: somebody
the bridges don't lift themselfs to make it possible for ships to travel below them. this even worked for submarines to submarines lurking under a bridge could be detected.
attention: bridge field is blocked for land units if a ship is below it and vice versa.