FIX: cursor frame was not correctly updated after player change

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6364 8aca7d54-2c30-db11-9de9-000461428c89
CODE: zeiger_t::set_bild should not have side-effects on area and marking

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6365 8aca7d54-2c30-db11-9de9-000461428c89