* update ppyolo_mobilenet_v3 large & small

* support visualdl in preprocess data

* support most preprocess op

* update solov2 some detail

* fix check paddle version

* add enable_static()

* follow comments

* remove blank line

* 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

add htc model 

Add gridmask and random erasing methods

add fleet training

* Add cutmix op(#88)

* filter illegal data

* update warning message

* optimize python path

* add yolov4

* Make logger less noisy

* Fix indent

* code for cornernet

* add doc

* refine custom op

* refine code from review comments

* refine doc

* update doc

* update code

* add cornernet_squeeze_mixup_cosine config

* update code

* update code

* fcos initialization

* delete the codes not used

* pre-commit the committed code

* delete the unused function

* modify the capacity in loader from 64 to 16