Improved docs and formatting for RemoteBlockInStream and TachyonFile
return false after exsits check failed
switched to directoryMode to make sure bin has the right perms
added file mode back
Merge pull request #561 from dcapwell/bintar

switched to directoryMode to make sure bin has the right perms
Merge pull request #560 from luogankun/luogankun05

return false after exists check failed
Update doc for new CLI commands
Merge pull request #562 from Huawei-Tachyon/jira74a

Update doc for new CLI commands
Merge pull request #558 from manugoyal/remote-read-docs

Improved docs and formatting for RemoteBlockInStream and TachyonFile
format