"Crumb" is a brilliant chronicle of the life and twisted times of a most unlikely bad boy, a skinny, four-eyed, sex-obsessed misanthrope with no weapons to fire back at the society that rejected him save one: The nerd can draw. It took director Terry Zwigoff six years to put together this absolute stunner of a documentary about R. Crumb, Robert to his cronies, the 51-year-old underground artist who has been using the comics to zap hypocrisy since his acidhead days in the San Francisco of the…