add faster rcnn\mask\cascade rcnn model arch\module\op
add base debug func in bufferdict 

clear directories & files for dygraph branch 

* add version check

* update version check & python version for cornerpool

Add `lr_multi_list` param for SSLD pretrained models' usage.

* activate scale_x_y

* update cspdarknet pretrained model

revert `reshape` changes

* fix with_background in export model

* fix coco_eval background

* filter illegal data

* update warning message

update optimizer doc

* test=master add some other lr scheduler

* test=master fix something and validate them

* optimize python path

* add yolov4

* Make logger less noisy

* Fix indent

* update check config

* fix slim/xx

* Revert back to `fluid.clip` for gradient clipping

current API is in flux, wait for it to stabilize

* Please CI

still buggy

* #add dcn on  FCOS_head and backbone

* 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

* add moile-side rcnn server model

* add iou aware module
* iouaware model zoo
* fix copyright

* add mobilenet v3 configs

* fix some comment

* fix memsize