Ellipse procedure

  DECLARATION:  Ellipse(X, Y: Integer;, StartAngle, EndAngle: Word;
                        XRadius, YRadius: Word);

      PURPOSE:  Draws an elliptical arc

         UNIT:  Graph

      REMARKS:  Ellipse uses the current line style and color and (X,Y) as
                the center point, and XRadius and YRadius as the horizontal
                and verticle axes.  The ellipse  will travel from StAngle to
                EndAngle.

 RESTRICTIONS:  Must first be in graphics mode.