FIX: in image_writer increase row_px_count after successfull read

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6763 8aca7d54-2c30-db11-9de9-000461428c89
CODE: allocate only as much memory as it will be used

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6764 8aca7d54-2c30-db11-9de9-000461428c89
FIX: some more correct combobox list ahndling

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6765 8aca7d54-2c30-db11-9de9-000461428c89