EDWARD Klein, the former New York Timesman who has made a career writing about the Kennedy family, has turned his sights on Sen. Hillary Clinton — and it won't be pretty, sources say. "He doesn't care for the Clintons, and he is digging up some new dirt on them," said one insider. Klein's titles include "All Too Human: The Love Story of Jack and Jackie," "Just Jackie: Her Private Years," "Farewell Jackie: A Portrait of Her Final Days," and "The Kennedy Curse: Why Tragedy Has Haunted America's First Family for 150 Years." Klein is almost finished writing the as-yet-untitled biography...