GitLab

* Add shape-aware grouping head

* Reformat docstrings

* Remove rewritten get_anchors in shape_aware_head

* Refactor and simplify shape-aware grouping head

* Fix docstring

* Remove fixed preset shape heads

* Add unittest for AlignedAnchor3DRangeGeneratorPerCls

* Add unittest for get bboxes in shape_aware_head

* Add unittest for loss of shape_aware_head

* Fix unstandard docstrings

* Minor fix for a comment

* Add assertion to make sure not all boxes are filtered