* 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

* update AvgPool2D to AdaptiveAvgPool2D
* class_num -> num_classes
* add en doc
* add googlenet to pretrained test
* remove weights name
* add parameter with_pool
* update en doc
* fix googlenet out shape
* 2020 -> 2021
Co-authored-by: Ainavo <ainavo@163.com>
Co-authored-by: Npithygit <pyg20200403@163.com>
Co-authored-by: Ainavo <ainavo@163.com>
Co-authored-by: Npithygit <pyg20200403@163.com>