fixed issue #665 to avoid add_string multiple times.
fixed small bug in previous commit #666
Merge pull request #666 from arulalant/master

fixed issue #665 to avoid add_string multiple times.
got wmo pictures and size ok
Merge branch '553_stretched_markers'
good pix with not-strecthced markers, final tweaks to default sizes
Merge branch '553_stretched_markers'
Updated baseline image for cdms_load_and_plot
Merge remote-tracking branch 'devel/fix_cdms_load_and_plot_baseline' into HEAD