wn_restore -- restore saved screen image

        USAGE

          wn_restore(wn)
          WINDOWPTR wn;

                wn - handle of previously wn_save(ed) window.

          Restores the screen image corresponding to the window handle
          wn, allocated memory is returned to the free list.

        RETURNS

          TRUE or NULL if error

        CAUTIONS

          This function should only be used with window handles obtained
          from wn_save.