* update dygraph export model

* delete get_export

* adapt faster and cascade

* add cascade mask

* add cascade rcnn

* update code

* remove comments

* add faster_rcnn_r50_fpn and faster_rcnn_r50

* update TestReader in dygraph

* if gt_ploy is empty, continue

* fix typo

* judge gt_ploy is empty or not

* fix judge condition

* fix gt_ploy judge

* add Mask R-CNN model

* fix mask rcnn eval

* fix mask rcnn infer

* fix mask rcnn config

* fix infer config

* add export_model and deploy

* fix travis-ci

* update CMakeList & linux doc

* update by comments

* adapt new im_shape im Mask R-CNN-FPN

* fix training

* split yolov3 loss using paddle op

* add sync_bn and modify list to LayerList to use sync_bn, add missing op, support cutmix op in dataset, modify reader to use new ops

* modify code according to review

* modify code to run eval.py successfully

* modify code to run eval and train successfully

* modify code to use mixup

* rebase code on lastest dygraph

* modify code to run in sync_bn mode

* modify code according to review

* modify target size of ResizeOp

* update mask_rcnn_fpn model

* update smooth_l1_loss

* update smooth_l1 and sigmoid_cross_entropy_with_logits

* fix relu name

* update reader in dygraph

* update dataloader some detail

* fix num_classes with background

* split config into models, optimizers, dataset, readers，runtime

* update YOLOv3 config

* add matrix nms api

* add test error in matrix nms ut

* modify code according to review

* modify matrix nms api

* add yolo_box and add unittest of yolo_box.

* update comment

* update sample code, call op in ppdet

* migrate roi_align and roi_pool to ops

* modify code according to review

* migrate detection ops from Paddle to PaddleDetection

* add unittest for detection ops

* update api & unittest

* add copyright & api name to migrate

* refactor dygraph & add mask rcnn fpn

* fix initialization & minor update

* refine architecture of mask_rcnn

add cascade rcnn and modify make net method
add new cfg method 
add auto debug tool

add yolov3

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