* add stylegan2 and pixel2style2pixel models, predictors and documents

* Integrate with visualdl
* visualdl: add doc and control paramter
* visual dl: move import, add install doc

* Add MidDaSv2 in ppgan.apps
* remove ppgan/apps/midas/run.py

* Update README
* Remove ppgan/faceutils/dlibutils/lms.dat
* Update apps.md

* Add AnimeGANv2 in link

* Update README_en.md

* add animeganv2 network and dataset
* animegan:refine code,add License
Co-authored-by: Nqingqing01 <dangqingqing@baidu.com>

* add ugatit model

* fix import and docs

* docs: update install instruction

1. paddlepaddle2.0.0rc instruction can be found from main page
2. only two steps, install paddlepaddle and paddlegan, other than 3step

* docs: update en install
* feat: add dcgan
* reform: debug with mnist datset
validate performance with different options, and original structure and setting

* refine codes docs

* fix pix2pix to_tensor

* fix apps

* refine duplicate frames and fix some bugs

* add face_parse predictor in apps

* remove duplicate frames and keep timestamp, fix psgan docs

* update Readme

* add art model of deoldify

* update demo

* update psgan pretrained model link in the tutorial doc

* Update README.md
* put jpeg center

* Refine some docs
* Update docs/en_US/data_prepare.md

* Update README
* Change docs dir to en_US and zh_CN
* Add paper reference
* Fix link

* refine codes docs

* add psgan and fom tutorial doc

* add video restore tutorial

* Add doc for Apps and refine some code
* Add how to switch cpu and gpu

* add docs

* update

* Add contribute doc
* Fix comments