transmissions.
*   Remove OpKernelConstruction::op_def() as part of minimizing proto
    dependencies.
*   VectorLaplaceDiag distribution added.
*   Android demo no longer requires libtensorflow_demo.so to run
    (libtensorflow_inference.so still required)
*   Added `categorical_column_with_vocabulary_file`.
*   Introduce ops for batching/unbatching tensors across Session::Run() calls.