Functions for display of images in external viewer SOG (http://www.starlink.ac.uk/sog/).
sog( label, loc )
label
may be any string which identifies the window
for display, so that multiple images may be displayed in different
windows without getting in each others' way.
loc
should be a filename or URL, pointing to an image in
a format that SOG understands (this includes FITS, compressed FITS,
and NDFs).
label
(String): identifies the window in which the image will be displayedloc
(String): image location