* 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

* support serialize/deserialize instance of custom class

* update version requirement of dependences

* remove requirements of unittest which are included in parl

* use fashion style of pyarrow serialization context; add thread safe unittest of serialize/deserialize

* add thread-safe test of remote module; add more exception tips of serialize/deserialize

* 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

* refine remote module, add heartbeat machanism and unittest

* yapf

* yapf

* support get ip address in CentOS, add dependence

* yapf

* add dependence in Dockerfile

* refine message_tag, Compatible with Python2 and python3

* refine unittest and comments

* remove ParlError, use to_pybytes api to compatible with Python 2 and python 3

* Not need to use to_pybytes

* use parl-test docker image for unittest, which has python2 and python3 env

* test different release order of sockets

* test for different closing way fo context and socket

* tmp commit for debug in teamcity

* tmp commit for debug in teamcity

* tmp commit for debug in teamcity

* use zmq.context destroy to close multi-thread socket, refine RemoteError

* set linger=0 for command socket in RemoteObject

* remove close context unittest

* fix codestyle

* fix codestyle

* rename parl.remote to parl.remote_class; will not exit client when having errors in function call; use sepereate server port in unittest to avoiding closing server manually

* rename parl.remote to parl.remote_class; will not exit client when having errors in function call; use sepereate server port in unittest to avoiding closing server manually

* fix typo

* remove unnecessary try/except in reply loop of client

* import RemoteManager to parl; refine comment

* run unittest in python2 and python3

* refine structure of repo

* refine structure of repo

* add --fix-misssing

* fix teamcity

* add --fix-misssing

* update paddle version in python2