* add cascade mask

* add cascade rcnn

* update code

* remove comments

* 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