* add Localization Distillation for Object Detection https://arxiv.org/abs/2102.12252

* fix lint

* fix lint

* fix lint

* fix lint

* fix lint

* fix config

* add kd detector

* edit loss name

* overide setattr but failed

* move init_detector into init

* seperate ld and gfocal, fix unused param error

* small fix

* small fix

* add test, reload magic function, create kd_loss.py

* del teacher model warnings

* fix reference

* add ignored bbox test fix docstring

* small fix

* docstring fix

* change names

* fix

* fix

* fix test

* fix import

* fix

* docstring fix

* fix

* retest

* add test

* docstring fix

* Move train_cfg/test_cfg into model

* fixed fsaf

* fixed missing

* clean op

* clean

* update build.yml

* fix setup

* change ci mmcv version

* change ci mmcv version

* add install pre-build mmcv instructions

* update mmcv url, move some unnit tests to mmcv

* update ci mmcv

* test

* test

* test

* fix unit test

* fix unit test

* fix onnx script

* update mmcv url

* fix typo

* fix some doc

* Bump version

* resolve comments

* Fix version bug

Co-authored-by: ZwwWayne <wayne.zw@outlook.com>

* add gfocal losses

* add gfl head, its related code, configs

* fix 2x config bug

* add most model and log in gfl README

* update gfl model and log

* Update transforms.py

modify variables  L, T, R, B   to  left, top, right, bottom

* Update gfocal_loss.py

modify variables into meaningful names:
* pt -> scale_factor
* a -> pos   b -> pos_label
* disl -> dis_left  disr -> dis_right
* wl -> weight_left  wr -> weight_right

* Update gfocal_loss.py

update formats

* remove duplicated get_bboxes/IoU calculation, make QFL consistent

* add all docstring in gfl_head.py and gfocal_loss.py

* Add upsample_cfg support in FPN

* small fix

* Add multiple extra conv sources

* small logical fix

* Add neck tests for fpn

* Add neck tests for fpn

* fixed several typos

* resolved issues

* Removed extra_convs_source option

* added necks to apis.rst

* change according to comments

* reconfigured configs

* Support V1.0 anchor generator

* Reformat code

* Add registry for anchor generator

* Reformat docstring

* fix isort

* Refactor anchor generator

* reformat doc, add unittest

* Refactor retinahead anchor generator

* Fix test_anchor device bug

* Fix docstring

* Resolve comments with more unittests

* Fix atss bug and add more unittest

* Resolve comments

* Add more asset and check

* fixed configs, add bypass_duplicate option

* rename _is_disjoint to _is_in

* delete work_dir in all configs

* add comment on work_dir priority

* add new config sample and check scripts

* context managere to prevent import

* refactor backbone, add caffe

* add fast rcnn

* all basci config done

* rm coco_proposal

* add scratch, wider_face, voc

* add reppoints

* delete device id, auto resume

* add libra_rcnn, ms_rcnn, nas_fpn

* add hrnet, fcos

* add free_anchor, gn, grid_rcnn, guided_anchoring, gcnet, ghm, gn+ws

* finished all, but some need refactor and unified logic

* fixed albu

* update ReseNet101

* reduce ResNet101, add norm_cfg, 4conv1fc

* refactor caffe backbone

* merge act_cfg, dcn from master

* rename 2fc head, add 4conv1fc head

* delete 4con1fc model

* rename components -> _base_

* flatten _base_

* refactor _base_ structure

* refactor config structure

* reduce _base/models

* rename all config

* add _coco inside configs

* fixed _coco in files

* fixed albu in test

* migrate to new sys

* fixed test

* fixed test

* rm cascade, fast_rcnn

* rm cascade, fast_rcnn from _base_

* fixed fcos_center

* rename from rule

* collopse third party model

* fixed test

* fixed some minor bug

* rename gn-neck_head -> gn-neck+head