Authorities in northeast Wisconsin are identifying the firefighter killed in a shooting Wednesday night in Appleton.   Fire Chief Jeremy Hansen says 14-year veteran Mitchell Lundgaard was responding to a medical emergency on a bus at the transit center when he was shot.  Investigators say a 47-year-old man from the Wausau area who was reportedly having seizures exchanged gunfire with officers and later died of his injuries.  A police officer and a female bystander were also hit during the shooting.  Lundgaard leaves behind a wife and three young children.