Merge branch 'master' into custom_op

# Conflicts:
#	docs/source/component/component.md
#	easy_rec/python/layers/keras/__init__.py
#	easy_rec/python/layers/keras/activation.py
#	easy_rec/python/layers/keras/numerical_embedding.py
#	easy_rec/python/model/multi_task_model.py
#	easy_rec/python/ops/1.12/libcustom_ops.so
#	easy_rec/python/ops/1.12_pai/libcustom_ops.so
#	easy_rec/python/protos/keras_layer.proto
#	easy_rec/python/protos/layer.proto
#	easy_rec/python/protos/tower.proto
#	easy_rec/version.py
#	examples/configs/dlrm_on_criteo_with_narydis.config