* fix compatibility issue with the newest paddle

* remove logging lines

* resolve the compatibility issue with the newest paddle

* yapf
Co-authored-by: Nrobot <zenghongsheng@baidu.com>

* Update train.py

remove create_actors thread in train.py

* Update GA3C train.py

* Limit impala to single GPU training

* refine comment of scheduler

* refine comment

* add learning curve for ES

* add learning curve for ES

* support new APIs of the cluster

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* rename learner.py

* Update README.md

* Update README.md

* Update README.cn.md

* Update README.md

* Update README.cn.md

* Update README.md

* ES example

* refine settings

* fix yapf

* refine documentation; remove csv logger

* fix bug

* merge learner.py and train.py; add version requirements of gym and atari_py

* unify actor num

* first pr

* start a worker when the master is started.

* First PR & Fix logger bugs.

* update docs for a2c, impala and ga3c

* update doc

* yapf modification

* update logger

* yapf correct

* yapf

* setup.py

* old setup.py

* worker 86

* intra-version: move parl.framework into parl.core.fluid

* add folder: parl.core

* remove former test folders

* yapf

* yapf0.24

* fix typo

* Update README.md

* Update README.md

* Update README.md

* soft depend on fluid; add module to monitor client status

* improve performance of IMPALA example

* fix bug of some client cannot exit normally

* refine comment

* .

* add IMPALA algorithm and some common utils

* update README.md

* refactor files structure of impala algorithm; seperate numpy utils from utils

* add hyper parameter scheduler module; add entropy and lr scheduler in impala

* clip reward in atari wrapper instead of learner side; fix codestyle

* add benchmark result of impala; refine code of impala example; add obs_format in atari_wrappers

* Update README.md