TensorFlow's core.
*   Improved multi-threaded performance of `batch_matmul`.
*   LSTMCell, BasicLSTMCell, and MultiRNNCell constructors now default to
    `state_is_tuple=True`. For a quick fix while transitioning to the new
    default, simply pass the argument `state_is_tuple=False`.
*   DeviceFactory's AddDevices and CreateDevices functions now return a Status
    instead of void.