Good cinema takes time. Matteo Garrone first thought of the idea behind “Dogman” in 2008. He had this image, that of “a few dogs, locked up in a cage, bearing witness to the explosion of human bestiality” (from the production notes). “Dogman” (Garrone’s fourth film in Cannes) is like a corroded fresco of an Italy that’s concealed from the sightseeing brochures. Like in “Reality,” or “Gomorra,” the characters