Co-authored-by: NFeng Ni <nemonameless@qq.com>

* add ttfnet enhance

* add doc

* fix pafnet training

* update README

* update doc, test=document_fix

* add citation

* update citation and ppyolo doc

* update readme en, test=document_fix

* update doc

* move ssld model, test=document_fix

* fix typo, test=document_fix

* add ppyolov2

* fix bugs and modify docs

* modify code and doc according to review

* fix bugs while resolving conflicts

* add PP-YOLO tiny

* add s2anet

* add pssdet model

* add senet

* add annotations according to review

* update slim model

* fix slim readme

* add Distill model

* add distill+prune

Co-authored-by: NGuanghua Yu <742925032@qq.com>
Co-authored-by: NFeng Ni <nemonameless@qq.com>

* add ssd config file, test=kunlun

* revise file format

* support mask_rcnn for kunlun

* support faster_rcnn for kunlun

* support ppyolo for kunlun

* update ppyolo_mobilenet_v3 large & small

* Update QUICK_STARTED_cn.md (#1757)

fix typo

* cherry-pick #1757 and #1473, test=document_fix

* add ppyolo_voc

* update solov2 some detail

* fix check paddle version