refine code

* Use iterable dataloader for image classification

* Support imagenet dataset with plain folder structure

* Add dali section to README.md

* Improve docs

* Remove some flags from docs

* Add dali reader for image classification

* Fix elapsed time calculation

* add profiler and max_iter for yolov3 model

* modify image_classification train

* update train.py

* modify args position

* fix shufflenet v2 bug

* move release 1.6 code to dev for tagging

* syn merged pr

* fix_infer_bug_release_some_model

* add aistudio link in README

* add_multiprocess_train_to_image_classification

test=develop

* update TensorRT 1.5.2 inference time

* add EfficientNet configuration in README

* add notes for the ported weight of EfficientNet

Add EfficientNet

* fix mobilenet bug

* fix inplce warning

refine image classification and add 19 pre-trained models.

* remove use_inplace=True and add save_step params

* remove useless params when using global pooling

fix lsr bug in image classification

* Refine Image classification

This reverts commit 5e41760f.

* fix SENet154_vd name

* add_license for PaddleCV

* update license date

* update GAN license date

* add densenet, squeezenet, darknet, resnext, resnext101_wsl pretrained models

* fix gpu detection issue on windows
1. use the fluid.core.get_cuda_device_count() to decide the GPU number
2. ignore the path missing issue

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

* 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>

* Reduce buf size in image_classification/reader
* Fix format

* refine readme and fix train bug

* Including Fluid and Fluid-TensorRT inference time.