'Cry-Baby' hits the high Waters mark BY LINDA WINER
Just how many high-school spoofs about the '50s can pop culture embrace?<br> The surprising answer to that question is . . . oh, all right, one more. "Cry-Baby," which opened last night at the Marquis Theatre, is pleasantly demented and - deep in the sweet darkness of its loopy heart - more true to the cheerful subversion of a John Waters movie than its sentimental big sister "Hairspray."