Katie ScullinSundance Grand Jury Prize-winner Shane Carruth, left, and Brothers Bloom writer-director Rian Johnson at the Magnolia last nightAs mentioned late last week, Brick-layer Rian Johnson was at the Magnolia last night for two Q&A's -- one after the 7:10 p.m. screening of his Brothers Bloom; and one before the 9:45 p.m. showing. The house was packed for both screenings, each filled with fans who knew every last detail of Johnson's 2005 debut and asked thoughtful questions about the so