Map header updates: Correct creation date in map header that was changed in r7448, it was using the wrong month; Update maps with entrance x & y coordinates, adjust map level difficulty to something slightly more realistic
git-svn-id: svn://svn.code.sf.net/p/crossfire/code/maps/trunk@10097 282e977c-c81d-0410-88c4-b93c2d0d6712