Billy Chapin, who as a child actor held his own against Robert Mitchum’s murderous preacher in Charles Laughton’s brilliant The Night of the Hunter, died Friday following a lengthy illness. His death was announced by his sister Lauren Chapin, the former child actress who costarred in TV’s classic family sitcom Father Knows Best. “It is with a saddened heart that I say ‘Good Bye’ to my precious brother Billy Chapin, wonderful Star of Movies, Television and Radio,” Lauren…