Symbol Modification

* add cycle_gan for dygraph

* upload download

* polish code

* fix bug

* fix some erro

* add infer

* refine code

* refine code

* matching bn

* add infer images

* update readme

* update readme

* replace pics

* Update README.md

* modified for conv2d

* 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

* support multi-process for resnet and transformer

* test=develop, hide build once usage

* test=develop, polish code

fix bug of gan in python3

* add ce for lexical_analysis

* add ce for lexical_analysis

* add ce for lexical_analysis

* add ce for lexical_analysis

* add warning for class_num mismatch

* change to value error

* add pbt lm; test=develop

* add dynamic ocr recognition; test=develop

* add unility.py; test=develop

* add readme; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix reader CACAHE_DIR_NAME; test=develop

* fix cache dir name; test=develop

* 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 ptb lm; test=develop

* add dynamic ocr recognition; test=develop

* fix renet bug; test=develop

* fix ocr save model; test=develop

* fix format; test=develop

* add pbt lm; test=develop

* add dynamic ocr recognition; test=develop

* add unility.py; test=develop

* add readme; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix bug; test=develop

* add cnn sentiment model for dygraph

* add pbt lm; test=develop

* add dynamic ocr recognition; test=develop

* test=develop

* Refine PE doc in dialogue_general_understanding for Windows users

* add pix2pix to gan library

* Add PaddleSlim CE

* Add log and remove counting

* Remove environment variable LD_LIBRARY_PATH

* Reduce epoch count to save time

* add tsm ce

* add tsm ce

* add enable_ce in configs

* remove enable_ce in val config

* add ce for dialogue_general_understanding

* add ce for dialogue_general_understanding

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