CANNES — The last episode of the seminal sci-fi saga "Star Wars" screened at the Cannes film festival Sunday, completing a six-part series that remains a major part of popular culture — and delivering a galactic jab to U.S. President George W Bush. "Star Wars: Episode III — Revenge of the Sith" was seen ahead of a celebrity-laden evening screening to be attended by its creator and director, George Lucas, and its cast, including Natalie Portman and Hayden Christensen. Reaction at advance screenings was effusive, with festival-goers, critics and journalists at Cannes applauding at the moment the infamous Darth Vader...