*   Infer `tf.contrib.distributions.RelaxedOneHotCategorical` `dtype` from
        arguments.
    *   Make `tf.contrib.distributions` quadrature family parameterized by
        `quadrature_grid_and_prob` vs `quadrature_degree`.
    *   `auto_correlation` added to `tf.contrib.distributions`
    *   Add `tf.contrib.bayesflow.layers`, a collection of probabilistic
        (neural) layers.