* update checkgpu

* Add faster_rcnn_x101_vd_64x4d_fpn_1x.yml
* Release faster_rcnn_r101_vd_fpn_1x.tar, faster_rcnn_x101_vd_64x4d_fpn_1x.tar, mask_rcnn_r50_2x.tar

* add save_inference_model in infer.py

* format code

* add comment

* add save_inference_model doc

* refine doc

* Fix some docs
* Unify COCO and VOC
* Change PASCAL to Pascal
* Unify dataset/coco

* add mobilenet_v2_x0_5, resnext50_32x4d, resnext50_64x4d, xception41 pretrained models
* Update README_cn.md

fix pickle.load to fit both python3 and 2

* Update README.md

* fix_save

* Transfer resnext50 multi-process multi-gpu changes from benchmark to models
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* refine code
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* improve quality of images

* update url for install doc

* add readme for ctcn metrics calculation

* fix code format in metrics/detections/README.md

* fix code format and add ``` in code lines

* Reduce buf size in image_classification/reader
* Fix format

* refine README & use a better visualization for doc

* fix typo in GETTING STARTED

* Update README.md and GETTING_STARTED.md for PaddleDetection.

* fix description of video in models/readme to be same as PaddleVideo/readme
* add c2d and i3d backbone in nonloal/readme
* fix table format of nonlocal/readme

* fix model zoo doc

* update yolov3/ssd bbox AP

* refine MODEL ZOO

* fix AP

* add size 416 320

* fix link

* fix format

* fix align

* add model zoo document file

* refine readme and fix train bug

* update darknet53 pretrain link

* update weights path