(svn r26263) -Fix [FS#5865]: Don't run into infinite recursion when getting next stopping station
-Fix: Don't rebuild the link graph overlay cache twice in a row
-Fix [FS#5860]: Update smallmap overlay if player joins different company and make sure company masks are valid
-Fix [FS#5865]: Really fix the infinite recursion problem and always consider all branches of conditional orders as possible next stopping stations.