GitLab

* add pvrcnn module code

* add voxelsa

* fix

* fix comments

* fix comments

* fix comments

* add stack sa

* fix

* fix comments

* fix comments

* fix

* add ut

* fix comments

* Add header for files

* Add header for files

* Add header for files

* Add header for files

* refactor PN SA module code

* refactor PAConv op & add PAConvSAModule

* add unit test

* add PAConvCUDA SA module

* add unit test

* minor fix

* merge master

* move paconv sa modules to a new file

* rename to BasePointSAModule

* rename to PAConvCUDASAModule

* delete typing comment

* refine docs

* rename mlp_spec to mlp_channel

* fix typos in comment

* add op fps with distance

* add op fps with distance

* modify F-DFS unittest

* modify sa module

* modify sa module

* SA Module support D-FPS and F-FPS

* modify sa module

* update points sa module

* modify point_sa_module

* modify point sa module

* reconstruct FPS

* reconstruct FPS

* modify docstring

* add pointnet2-sa-msg backbone

* modify pointnet2_sa_msg

* fix merge conflicts

* format tests/test_backbones.py

* [Refactor]: Add registry for PointNet2Modules

* modify h3dnet for base pointnet

* fix docstring tweaks

* fix bugs for config unittest
Co-authored-by: ZwwWayne <wayne.zw@outlook.com>