Map display

A few mostly cosmetic changes have been introduced here. Displays involving greyscales will mostly now have a scale-bar displayed wherever there seems to be most room. This is not foolproof however, and for some unfortunately sized maps the scale-bar may vanish off the edge of the plot area - just do SET-MAP-SIZE if this is the case. Note that the scale bar will not appear in the case of PLOT-LINE-PARAMETERS when more than one map is made -- the various maps in this case have different scales, and it did not seem sensible to try to generate scale-bars for each independent panel.

Also, you can now display RA and Dec coordinates (only) in all forms of map display (GRID, CHANNEL-MAP, GREY, CONTOUR and PLOT-LINE-PAR) in standard sexagesimal notation. That is, absolute positions are displayed, in HMS and DMS respectively. You can however still display things in the old way if you want - the map centre RA and DEC are now indicated in the axis labels. Use SET-MAP-PARAMETERS to change the default axis scaling.