add lpip-tensorflow

lpips-tensorflow/.gitignore

lpips-tensorflow/.gitmodules

lpips-tensorflow/LICENSE

lpips-tensorflow/README.md

lpips-tensorflow/export_to_tensorflow.py

lpips-tensorflow/lpips_tf.py

lpips-tensorflow/requirements-dev.txt

lpips-tensorflow/requirements.txt

lpips-tensorflow/setup.py

lpips-tensorflow/test_network.py