Autoregressive autoencoder model.

def autoencoder_autoregressive():
  """Autoregressive autoencoder model."""
  hparams = autoencoder_basic()
  hparams.add_hparam("autoregressive_forget_base", False)
  hparams.add_hparam("autoregressive_mode", "none")
  hparams.add_hparam("autoregressive_decode_steps", 0)
  hparams.add_hparam("autoregressive_eval_pure_autoencoder", False)
  hparams.add_hparam("autoregressive_gumbel_sample", False)
  return hparams