BN
SyncBN
* [Feature] Support convert BN to SyncBN by config * make unit test compatible with cpu * Fix as comment * fix unit test * change signature of convert_sync_batchnorm: rename sync_bn to implemention * fix unit test * fix unit test
* [Docs] Fix api files of en docs * minor fix
* [Docs] Add readthedocs.yml * include torch in readthedocs.yml * add torch torchvision in docs.txt
* [Docs] Make API of docs clearer * minor fix * fix md format