FIX initialization

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7433 8aca7d54-2c30-db11-9de9-000461428c89
FIX crashes if world is destroyed after loading without a sync-step being performed

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7434 8aca7d54-2c30-db11-9de9-000461428c89