AURORA — A gunman slipped into a midnight premiere of the new Batman movie through an emergency exit early Friday, tossed two hissing gas canisters and then methodically, calmly walked up the aisle firing, killing 12 people and wounding 58. It was among the worst mass shootings in American history. Terrorized moviegoers, some dragging bloodied bodies, spilled out of the Century Aurora 16 complex...