GitLab

* add multi backbone

* update multi backbone

* update multi backbone

* update multi backbone

* modify multi backbone

* modify multi_backbone params

* modify docstring

* update multi_backbone unittest

* modify docstring

* Add centerpoint_rpn and scn, change pillar encoder and voxel_encoder

* Move test_voxel_encoders.

* Change names, add docstring.

* Reconstruct centerpoint_rpn.

* Add centerpoint_rpn.

* Change SECONDFPN, delete centerpoint_fpn

* Remove SparseBasicBlock.

* Change SpMiddleResNetFHD to SparseEncoder.

* Finish SparseEncoder unittest.

* Change test_hard_simple_VFE.

* Change option, add legacy.

* Change docstring, change legacy.

* Fix legacy bug.

* Change unittest, change docstring.

* Change docstring.

Update mmdet3d/core/bbox/structures/base_box3d.py, mmdet3d/core/bbox/structures/lidar_box3d.py, mmdet3d/core/post_processing/box3d_nms.py files

Update mmdet3d/models/dense_heads/anchor3d_head.py, mmdet3d/models/dense_heads/free_anchor3d_head.py, mmdet3d/models/dense_heads/parta2_rpn_head.py, mmdet3d/models/dense_heads/train_mixins.py, mmdet3d/models/dense_heads/vote_head.py, mmdet3d/models/roi_heads/bbox_heads/parta2_bbox_head.py, mmdet3d/models/roi_heads/mask_heads/pointwise_semantic_head.py, mmdet3d/models/roi_heads/roi_extractors/single_roiaware_extractor.py, mmdet3d/models/roi_heads/base_3droi_head.py, mmdet3d/models/roi_heads/part_aggregation_roi_head.py files