AtariWrapper does not use recommended defaults

The current AtariWrapper by default has `terminate_on_life_loss` set to True. This goes against the recommendations of Revisiting the Arcade Learning Environment (https://arxiv.org/pdf/1709.06009.pdf). I believe this should be set to False by default. They also recommend using sticky actions instead of noop resets, but I think that problem is outside the scope of this wrapper.