Hot weather means hot box office. From now to Labor Day nearly 100 new films will be screaming "look at me." Be warned. For every sizzle (Who Framed Roger Rabbit, A Handful of Dust), there's a fizzle. A big star (Sean Connery in The Presidio) or a hard-sell sequel (Poltergeist III) may lure you into a not-so-hot time at the movies.