Juliette Lewis Is a Natural Born Rebel       There are radicals, and then there is Juliette Lewis, the wildly unpredictable, Oscar-nominated actress-turned-musician, whose rich life story runs the gamut from emancipation and aliens to chemical dependency and Brad Pitt. After a three-year absence from the silver screen, the stunning provocateur cracks the whip with four new films and her most assured album yet.   Those wild eyes of hers go all cat’s-tail-in-the-light-socket electric and Juliette Lewis lets out a howling “Whoooaaa!”—to nobody, apparently, but herself. Lewis is what you might call a self-motivator. Whenever the energy begins to dip on set during the daylong shoot for this rebels-inspired story, which sees her step into the many-storied heels and platform boots of such diverse firebrands as Bettie Page, Coco Chanel, Bonnie Parker and Mick Jagger, Lewis flips her inner switch and ramps it up a notch or 10.   That special wildfire in her eyes is a familiar sight for fans of her incendiary on-screen performances—the crazed pupils of, say, Mallory Knox in Oliver Stone’s Natural Born Killers—or her on-stage presence, as the frontwoman for the (now-disbanded) rock group, Juliette and the Licks.   “She summons it,” says actor Mark Ruffalo, who directed her in