Saturday was opening night for Sacramento Theater Company's holiday hit, "Cinderella” Imagine British pantomime, a vaudeville act and musical comedy with a little Beach Blanket Babylon thrown in. The show is definitely interactive. Director Peggy Shannon started things off by having the audience do a warm-up by yelling back at the characters. And the characters don't just address the fourth wall, they blast through it. The plot is well known, but in this version a lot of topical humor and inside jokes are thrown in. The acting is excellent; many of the actors have appeared in previous STC productions of "Cinderella." This includes Michael RJ Campbell as Goneril and Brian Rodda as Regan, t