* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* print the signatures of the apis

* some faults, and a test case

* use the FullArgSpec as the ArgSpec, repr>str

为了延续脚本历史，把FullArgsSpec替换为ArgSpec；在逆转回对象时，记得加上inpect.FullArgSpec对象

* script form @zhiboniu

* parsearg

* read argspec from file

* add comments

* refactor check_compatible and its testcases

* skip the empty ArgSepc()

* update the function, get inspect.FullArgSpec instances directly.

* typo

* for the functions using inner-defined VarType or other Class Type not accessable, use the string comparements.

* typo

* logging added

* 若变量和默认值都增加了，用负数索引需要再处理下这个增加的内容

* defaults itself may be NoneType

* defaults added 2 items when args only added 1 item

* same as the previous comment

* enable the check_api_compatible.py

* run test_check_api_compatible.py

* sort the output of print_signatures.py