delete old code

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6535 8aca7d54-2c30-db11-9de9-000461428c89
CODE cleanup: calculate height-to-climate table in karte_t, create ground textures only once per lifetime

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6536 8aca7d54-2c30-db11-9de9-000461428c89