My favorite installation at MoMA PS1's quinquennial Greater New York was Dean Millien's assemblage of city rats and cats made of aluminum foil. It was impressive, charming, and refreshing. There's a good story behind these silver animals: As a child, Millien’s toys were thrown away, so he made his own from aluminum foil. Today, Bryan Martin visits the self-taught artist's studio in Brooklyn to hear from him about sculpture, disability, and his c…