*   Add `tf.contrib.bayesflow.layers`, a collection of probabilistic
        (neural) layers.
    *   Add `tf.contrib.bayesflow.halton_sequence`.
    *   Add `tf.contrib.data.make_saveable_from_iterator.`
    *   Add `tf.contrib.data.shuffle_and_repeat`.
    *   Add new custom transformation: `tf.contrib.data.scan()`.
    *   `tf.contrib.distributions.bijectors`: