NEW YORK — Isaac Mizrahi showed what a wild and crazy guy he really is. His energetic, upbeat fall collection had the old Isaac spirit — and an almost unbelievable array of eye-popping colors. There was everything from pepto pink to orange and aqua, all in the form of newly proportioned, great-looking clothes. Rubberized tweed raincoats, camel peacoats and sharp short suits were among the stars. Here, a runway look.