* update directory structure to support the icode platform

* remove source code generated by protobuf

* move code into the core directory

* remove depedence on predictor.clone()

* remove commented lines

* remove FATAL logging

* remove ESAgent's construnction function based on cxx_config

* mv prototxt

* rename SamplingKey to SamplingInfo

* add asynchronous lsagent

* rename AsyncAgent to AsyncESAgent

* fix comments

* Update async_es_agent.cc

* Sampling Info

* commemt

* commemt