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

* 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