* update solov2 some detail

* fix check paddle version

* add enable_static()

* follow comments

* remove blank line

* add ppyolo mobilenetv3

* share train_batch_size from reader to model

* update floor_divide

* add makedirs for dumping config

* add solov2 model

* fix train batch size

* add solov2_r101_vd_fpn_3x

* fix batch size and update modelzoo

* refactor code of solov2

* fix deploy/python

* warning when YOLOv3Loss.batch_size setting

* add batch_size in YOLOv3Loss for backward compatable.

* sync TrainReader.batch to global train_batch_size

* fix deadlink in docs/tutorials/INSTALL_cn.md, slim/README.md and slim/extensions/distill_pruned_model/README.md

* update version require for ppyolo

* add COCO test-dev eval config and doc

* add PPYOLO
Co-authored-by: Nlongxiang <longxiang@baidu.com>

add htc model 

* Add `matrix_nms` op

* Make OP registration more robust

* update mbv3 ssdlite

* fix ssdlite link

* Adapte softnms for YOLOv3

* Add ACfpn, `CxAM` and `CnAM` is not included here.

* add version check

* update version check & python version for cornerpool