AJ Schnack returned to SILVERDOCS last night with the world premiere screening of his latest, Convention. Schnack received the festival’s Cinematic Vision Award a few years back for his About a Boy, an elegiac tribute to Kurt Cobain featuring taped interviews with the singer combined with filmed images of the places where he lived and grew up. It was an acquired taste as a film, but even its detractors couldn’t deny it’s simple beauty….