This episode's headline: The Unabomber?; Assisted Suicide; Changing Times. ANCHOR: JIM LEHRER; GUESTS: JOHN O'BRIEN, Chicago Tribune; DAVID JACKSON, Time Magazine; MARGARET BATTIN, University of Utah; DR. MARK SIEGLER, University of Chicago; CORRESPONDENTS: ELIZABETH FARNSWORTH; LEE HOCHBERG; MARGARET WARNER; FRED DE SAM LAZARO;