NAME: GetAspectRatio

     USE: Procedure to return the effective resolution of the graphics
          screen. The aspect ratio is a value that can be computed by
          dividing the first parameter (XAsp) by the secord (YAsp).
          This value can be used to make arcs and circles round.

     DEPENDENCY:  Must first be in graphics mode.  The unit Graph
                  must also be placed in the uses section.

     SYNTAX: GetAspectRatio(Var XAsp, YAsp : Word);