Fix pb_protobuf2 FromString problem

Fix str and bytes problem
Fix sorted problem
Fix math problem
Fix CI problem

Fix pserver can NOT start with DebugString problem

fix: add batch size check in loading data process

Add tensorrt elementwise add

* api clean

* update API.spec

* "cherry picked cpp tests"

* "cherry picked"

* "cherry picked tests"

* "merge develop branch"

* "add gradient register"

* "make some enhance"

* "better format"

* "fix typo"

* "fix reuse"

* "fix get expected kernel"

* "change the mkldnn code"

* "fix mkldnn"

* "fix mkldnn failed test"

* "add comment"

add conv2d trt converter

fix warning

* reopen test_parallel_executor_transformer

* save the CPU runing time