* set lr.persistable=True

* comment fuse flag

* move benchmark changing of cycle gan to models/develop, test=develop

* add flag exist check, test=develop

This changing can improve performance

test=develop

* update

* fix

* Enable the use of python multi-processes to read data.

* Add the setting of default value of some paddle flags, such as GC.

* fix padding bug and add resize_short_size args

* fix typo

* pass args:settings in eval and infer

* Fix SSD file path.

* Move object_detection to ssd.

* add landmark models

* modify single queue to a queue per process for data processing

* add transforms.py and rename torchvision_reader.py to reader.py

* add datasets.py

* remove pytorch apis

* fix some small bugs

* remove torch and torchvision from requirements.txt

* modify core.CUDAPlace to fluid.CUDAPlace

* bug fix: data_dir has no effect

* bug fix: data_dir has no effect

* bug fix: modify  in directory

* bug fix: fix a typo in README.md

* update image classification pretrained models

* update softmax

* Add mixup and distill and fix bugs

* recover test pyreader

* add error tip

* update README_CN

* fix distill bug

* add reader_cv2.py

* update run.sh

* fix docs

* fix typo

* polish train.py

* fix typo

* remove commented code

* fix typo

* fix_typo

* recover scale_loss

* fix typo

* fix bug

* fix test_program bug

* add yolov3 label_smooth faq

* refine en

* fix bug in cycle and pix

* add yolov3 save_inference_model example

* add save_inference_model in infer.py

* refine link

* refine yolov3 doc en.

* fix format in README.md

* refine FAQ

* refine en doc

* add zh doc

* refine zh doc

* use zh as default

* add infer config

* add data descp

* add transforms.py and rename torchvision_reader.py to reader.py

* add datasets.py

* remove pytorch apis

* fix some small bugs

* remove torch and torchvision from requirements.txt

* modify core.CUDAPlace to fluid.CUDAPlace

fix bug of gan in python3

* add warning for class_num mismatch

* change to value error

* modify .run_ce.sh

* modify .run_ce.sh

* test=develop fix error while loading cv2.VideoCapture

* test=develop
fix bug of index out of range in SampleFrames

* fix bug

* add pix2pix to gan library

* add tsm ce

* add tsm ce

* add enable_ce in configs

* remove enable_ce in val config

this is for issue #2232
add pretrain description in readme to show that some models need pertained models to begin training.