add logs and fix a python path bug

* add master server unit test

* fix comments

* use t.Log

* fix travis can not fetch git repo

* fix git repo

* fix recordio split and task passes

* update for pre commit

* update

* update, still need to sync client wait for pass end.

* able to sync passes for task dispatching

* update to comment

* update

* fix yapf check

* why local pre-commit fails? version is the same

* fix race condition

* update

* fix race condition

* this still have duplicate problem in unit test

* update

* update

* update by comment

* update

Unchecked errors could be handled by: cd go; gometalinter --vendor --disable-all --enable errcheck $(glide nv)

* using etcd as fault tolerant training

* update

* workable version, ft not tested

* small fix

* update

* remove TODO

* init etcd cclient

* add etcd

* add etcd.go

* fix compile problem

* move code to etcd.go

* add etcd_lister.go for pserver client

* add etcd_client_test.go

* merge etcd_client_test and client_test

* refine client_test.go

* refine code

* format code

* add TODO and use interface instead of struct

* fix typo of initDesiredPservers

* optimize dir structure of go/pserver/client

* add a flag to config index for pserver

* follow comment

* fix path

* optimize code

* remove err in pserver NewEtcd

* restore comment about /ps_desired

* add trainer library

* modifty file name

* move trainer to master client

* update

* update

* modify monitor master to receive a chan

* update

* use etcd client from etcd_client.go

* update

* update

* remove etcd client without lock

* update

* update the comment

* update commonts