* refine doc for api Program, BackwardStrategy, default_start_up_program

* remove wrong binary char to make file not binary

* delete binary file and push a new file as regular one

* change name back since we delete bianry Program_cn on develop

* refine clone doc

* remove additional gitignore

* refine doc about some info

* refine doc about some info

* refine doc about some info

* refine doc about some info

* refine doc about some info

* remove useless info

* refine doc

* fix code

* fix doc error in Program_cn.rst

*  add code and refine doc

* refine clone doc

* fixed one error of api_cn

* fixed some errors of api_cn

* fixed some errors of api_cn

* fixed two errors.

* fixed two errors

* fixed one error.

* fixed one error

* fixed one error.

* fixed two errors.

* fixed one error.

* fixed two errors

* fixed two links

* synchronize api_cn with the api_en of develop.

* updated develop/api_cn

* update the api_cn of develop

* update api_cn of develop

* fixed some errors

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* fixed some wrong links

* fixed two links

* fixed two links and some error.

* fixed some errors.

* fixed two links