FIX: uninitialized variables that could spoil route search

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6802 8aca7d54-2c30-db11-9de9-000461428c89
FIX another uninitialized variable

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6803 8aca7d54-2c30-db11-9de9-000461428c89
FIX: accept double-slope parameter for set-slope tools

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6804 8aca7d54-2c30-db11-9de9-000461428c89
FIX: haltestelle_t::all_koords only usable during loading of savegame; some code cleanup

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6805 8aca7d54-2c30-db11-9de9-000461428c89
FIX display of viewport region on minimap for very mountaineous terrain

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6806 8aca7d54-2c30-db11-9de9-000461428c89