* DCN cpu version
* add modulated dcn cpu version
* move deform_conv_shape_check to deform conv utils
* add inline to deform_conv_shape_check
* add tests
* run linter
* add newline at file end
* run pre-commit against modulated deform conv cpp
* update saconv test
* run clang-format
* remove cuda device inline
* refactor dcn cuda/cpu functions
* remove DCN util
* remove DCN util hpp from all included files
* Addressing PR comment by refactoring modulated-DCN
* fix lint in cpp files
* improve digit_version & use it for version_checking
* more testing for digit_version
* setuptools >= 50 is needed
* fix CI
* add debuging log
* >= to ==
* fix lint
* remove
* add failure case
* replace
* fix
* consider TORCH_VERSION == 'parrots'
* add unittest
* digit_version do not deal with the case if 'parrots' in version name.
* fix fp16 bug on DCNv2
* support fp16 on DCN/DCNv2 when pytorch >= '1.6.0'
* add comment
* Modified the comments
* Unified the usages of '.to()' and '.type_as()'
* add ext ops, support parrots
* fix lint
* fix lint
* update op from mmdetection
* support non-pytorch env
* fix import bug
* test not import mmcv.op
* rename mmcv.op to mmcv.ops
* fix compile warning
* 1. fix syncbn warning in pytorch 1.5
2. support only cpu compile
3. add point_sample from mmdet
* fix text bug
* update docstrings
* fix line endings
* minor updates
* remove non_local from ops
* bug fix for nonlocal2d
* rename ops_ext to _ext and _ext to _flow_warp_ext
* update the doc
* try clang-format github action
* fix github action
* add ops to api.rst
* fix cpp format
* fix clang format issues
* remove .clang-format
Co-authored-by: Kai Chen <chenkaidev@gmail.com>