wn_move -- move window

        USAGE

          wn = (WINDOWPTR)wn_move(wn,row,col)

                wn -  handle of window to be moved
                row - destination row
                col - destination column

          Moves the window corresponding to wn to a new location.  The
          cursor is positioned off the screen after the call.

        RETURNS

          Window handle of the window moved or NULL if error.

        CAUTIONS

          The window "wn" automatically becomes the top window tile upon
          return.