This will serve as both a review and a testimonial. Mel Miller, the artistic director of Musicals Tonight!, has announced that "Calamity Jane," his hundredth production, will be Musicals Tonight!’s last. For two decades he’s produced vest-pocket versions of musicals ranging in original size from intimate to enormous, and ranging in fame from household-word to incredibly obscure. He’s given us operetta ("Mlle. Modiste," "Naughty Marietta"), New York premieres of good West End shows ("Hoi Polloi," "Love from Judy"), Broadway flops that improved on his small stage ("My Favorite Year"), out-of-town casualties by major writers ("That’s the Ticket"), and musicals we