It maybe could have used some tightening, but 'Catch Me If You Can' is still the most purely fun Steven Spielberg film since his incredible decade-long streak as a master entertainer (from, say, 1975 to 1985, when he started yearning to sit at the grown-up table with 'The Color Purple').There is nothing in particular riding on the movie, no stentorian tributes to historical courage; it is just Spielbe