-Fix: Don't rebuild the link graph overlay cache twice in a row

git-svn-id: http://svn.openttd.org/trunk@26265 6aa0318a-3be1-0310-93fa-89fd2396df07
-Fix [FS#5860]: Update smallmap overlay if player joins different company and make sure company masks are valid

git-svn-id: http://svn.openttd.org/trunk@26266 6aa0318a-3be1-0310-93fa-89fd2396df07
-Fix [FS#5865]: Really fix the infinite recursion problem and always consider all branches of conditional orders as possible next stopping stations.

git-svn-id: http://svn.openttd.org/trunk@26267 6aa0318a-3be1-0310-93fa-89fd2396df07