CONLABB   Controls the boxing of High and Low labels on all contour plots
           (*PCON).  See 'HLB' in the NCAR Graphics Guide to New Utilities (one
           INTEGER value, default is CONLABB = 0).
           
           CONLABB = 0 - High and low labels are not boxed at all.
           CONLABB = 1 - Perimeter of the bix is drawn (in the same 
                         color as the label) after the label is drawn. 
           CONLABB = 2 - The box is filled before the line is drawn.
           CONLABB = 3 - Both 1 and 2 above.