* only master machine saves plan and has event logger

* separate Data, Persistence, Cache, Log FileSystem config

* refine

* only specify data and snapshot path conf

* forbit multiple machines use localfs as snapshot fs

* networkfs as localfs

* refine

* Store log to snapshot (#1109)

* use machine id, drop machine name

* ensure setting machine id

* allow save snapshot to localfs for distributed training (#1113)

* Snapshot to master (#1116)

* allow save snapshot to localfs for distributed training

* fix mdSave to master for model parallel

* fix review comment issues

* add sanity check for machine id

* rm useless comments

* update example

* Dev refine runtime add log stream mgr (#1142)

* add LogStreamMgr

* refine and refactor OutStream=>LogStream

* bugfix

* use LogStreamMgr to write graph, dot, plan, profile and proto

* refine

* simplify, remove LogStreamMgr (#1243)

* simplify, remove LogStreamMgr

* TeePersistentLogStream add static factory (#1244)