Peanut butter and jelly. Milk and cookies. Gin and tonic.  Some things just go better when mixed, as demonstrated in Alexis Mabille’s Spring 2010 Couture show. The French designer, with a resume that includes YSL and Dior, is relatively new to the fashion world and one of the few brave enough to compete in the woefully fading world of couture. Mabille’s spring collection showcased the young designer’s skillful cutting and attention to detail with geometric shapes and color blocking from head to toe. Here are some mixed-up looks that go together better than lox and cream cheese. Well, maybe not that well….