FIX: full width makeobj images again

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6766 8aca7d54-2c30-db11-9de9-000461428c89
FIX imagewriter: write all pixels but to do not read out-of-bounds

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6767 8aca7d54-2c30-db11-9de9-000461428c89