* 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

* fix a number of bug

* update comments

* paddle license

* revert the change on client_not_init_test.py

* fix timeout bug & unnitest

* add unit test for potential bugs

* yapf

* unit test

* logger

* logger#2

* fix job's bug that will cause dead-lock

* fix bug

* add missing files

* solve hanging

* fix comments; exit job completely

* hanging problem

* hanging problem#2

* hanging_program#3

* CMAKE

* remove unused variables

* fix the compatibility issue

* fix the comment issue

* support paddle 1.5.1 and replace PE with compiler

* yapf&copyright

* yapf

* fix the teamcity problem

* fix the teamcity problem

* fix comment

* only support paddle 1.5.1

* Cmake

* fix comment

* add documentaion for basic classes

* change the order of three basic classes

* fix commemt & yapf

* comment #2

* yapf#3

* fix commemt@zhs

* minor change

* modify comment

* Update algorithm.py

* Update agent.py

* Update algorithm.py

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

* add folder: parl.core

* remove former test folders

* yapf

* yapf0.24