FIX: set karte_t::load_version to most current format after loading is finished

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7054 8aca7d54-2c30-db11-9de9-000461428c89
FIX crash if vehicle has zero capacity

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7055 8aca7d54-2c30-db11-9de9-000461428c89
FIX: connect rivers to the sea properly

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7056 8aca7d54-2c30-db11-9de9-000461428c89
FIX: display city status correctly

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7057 8aca7d54-2c30-db11-9de9-000461428c89
FIX: tunnel and bridge makeobj/reader wrong

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@7058 8aca7d54-2c30-db11-9de9-000461428c89