* add implementation of RetinaNet

* * add README.md and model zoo
* rename FOCSFeat -> RetianFeat
* add mstrain model to model zoo
* refactor DeltaBBoxCoder

* update link for model and log

* fix problem of s2anet while deploying

* correct problem of s2anet TestReader

* add dota default category

* add mcfairmot train eval export code

* fix eval and export

* update modelzoo

* add hrnet18_dlafpn

* unify jdetracker

* fix deploy infer for single class

* fix multi class fairmot deploy

* fix mcmot data source and deploy

* fix num_identities

* fix num_identities_dict

* add sge attention on fpn

* add iou head

* add config, fix head

* fix iou offset weight

* fix fairmot centerhead

* add centernet

* add centernet

* add r50 for centernet

* support deploy for centernet

* add doc

* update pretrain

* clean code

* update r50 doc

* unify for_mot

* update code according to review

* update doc

* refine preprocess

* update doc

* update PicoDet Architecture and config

* update picodet inference deploy

* [dev] add TOOD

* fix link and notes

* replace ConvNormLayer

* Update PicoDet adn GFl

* set lr for 4 card as default, and update

* s2anet update

* remove np anchor

* add gfl model and PicoDet

* clean code of s2anet

* fix for paddle==2.1.0

* remove debug info

* update comment

Besides removing unnecessary imports, this also fixes the missing logger module in test_architectures.py within the static directory.

* add sparsercnn

* update sparsercnn

* Add DETR

* drop return_pad_mask in PadBatch

* fix bs=2 of FCOS

* fix bs=2 of ttfnet

* fix cascade deploy

* speedup by paddle.expand

* reorganize the code, and fix bug

* fix typo

* remve comment

* reorganize code

* Revert "reorganize code"

This reverts commit 4f928c3a46b264ba8815978b914bf81a46b66b62.

* set weight

* set default config

* fix code style

* add solov2 enhance model

* support --eval for s2anet

* add spine dataset and config yml for s2anet

* add doc for s2anet

* update doc

* fix typo, test=document_fix

* add some comments, and update import