cleanup

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7031 8aca7d54-2c30-db11-9de9-000461428c89
sqapi: export list of attractions

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7032 8aca7d54-2c30-db11-9de9-000461428c89
sqapi: add building_x::is_same_building, properly implement map_object_x constructor

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7033 8aca7d54-2c30-db11-9de9-000461428c89