* add quickstart doc, roadsign dataset

* add ppyolo r18vd mbv3, yolov3 r50vd

* modify TestReader of ppyolo mbv3 r18vd

* add clip to avoid nan, modify ema to apply ema on bn mean and bn var

* fix code resulting in nan

* add yolov3 r50vd dcn configs

* finish yolo_series and fix some problems

* hide --bias flag and modify docs

* modify --bias and fix deploy/python/infer

* refine dygraph config, test=dygraph

* fix fcos config

* add mbv1v3-yolov3

* add ssd mbv1v3 voc

* yolov3 mbv1v3 voc

* training log fix

* yolov3 voc fix

* yolov3 mbv1v3 training and eval, ssd fix

* add syncbn

* mbv1v3 clean code

* mbv1v3 clean codes

* remove ssd mbv1v3

* update modelzoo doc

* remove others

* fix ssd reader and prior_box

* ssd mbv1 config

* fix anchor steps and reader op

* ssdlite mbv1v3 infer and train

* update yolov3 config and modelzoo

* update yolov3_mbv3 modelzoo

* pre commit update

* update modelzoo

* fix mbv3 in yolov3

* fix precommit
Co-authored-by: Nnemonameless <nemonameless@qq.com>