By COLLEEN BARRY, AP Fashion Writer FLORENCE, Italy (AP) — Alessandro Michele has radically shifted Gucci codes and challenged fashion norms in his 6½ years as creative director of the brand founded by Guccio Gucci as a travel bag company in Florence 100 years ago. To mark the centenary, Michele has curated an exhibition in the Gucci Garden gallery, on Florence's Piazza della Signoria, that underlines