* initial commit

* minor fix

* remove redundency

* address comments

* Save the inference model in Python example of recommender_system.

* Add infer() in Python unittest recommender_system.

* Add C++ inference unittest of recommender_system.

* First basic implementation

* Add infer example for image_classification

* Address review comments: round 1

Enable whole-archive flag in cc_test and use cc_test to rewrite the CMakeLists.txt of inference unittest.