AUSTIN, Texas — The gunman who killed three people and wounded more than a dozen others in a mass shooting at a downtown Austin, Texas, bar in March was a “lone actor” and there is no evidence he was supported or directed by a foreign terrorist group, FBI investigators said Thursday. The agency released a two-page updat e of its investigation into the attack on Buford’s Backyard Beer Garden in the early morning hours of March 1 that ended when gunman, Ndiaga Diagne , was killed by police. The