* Polish function code

* Rename funciton to engine

* Fix Log msg and doc

* Rename Function to Engine and using new Function class to warp Engine

* Rename EngineInfo

* Adjust member variable order

* Move Function classes to a sub dir

* Format code

* Remove include fluid head files in JitLayer

* Format code

* Remove const to fix ci error

* Fix param error

* Polish jit layer include and cp some headers to python/include

* Fix comment

* [JIT]Layer support eager dygraph mode and polish Function interface

* remove usless code

* fix #define

* Pybind JitLayer VarBase Function and add python UT

* Add multi program load UT

* Fix UT place error

* Update jit.save param name

* Remove some comments

* Polish cmakelists

* Polish JitLayer in Python

* Fix comments

* Polish Layer code

* Refine some api name

* Polish load program code

* Clean smoe include

* Process windows style path

* Move some funtions to utils

* Split layer_utils.cc and polish interface BaseFunction

* Polish include

* Fix cmake for funciton_schema

* Using unordered_map replace map and rename VariableNameMap

* Polish Layer Constructor and remove useless include

* Refine compilation_unit