* update solov2 some detail

* fix check paddle version

* add enable_static()

* follow comments

* remove blank line

* optimize python path

* update check config

* fix slim/xx

* add blazeface nas demo

* fix format

* fix configs

* fix reduce_rate

- 1.add cn docs
- 2.fix fddb evaluate
- 3.fix get_shrink
- 4.delete FLAGS.dataset_dir

* Polish Reader to simplify preprocessing logic.
#  sample_transforms-> make batch -> batch_transforms in Reader.
* Clean some code
* Imporve yolov3_r50vd_dcn_obj365_pretrained_coco 41.4 to 41.8.
* Update all configs.

* update code & doc

* Add face detection configs and main code.
* Integration multi-scale evaluation.