Snapshot console

call snapshot console ommand if there are are arguments to snapshot
Merge branch 'issue#395_snapshot_cli' of git://github.com/sujeetsr/rockstor-core into sujeetsr-issue#395_snapshot_cli
Use api_error decorator for share detail and snapshot consoles
fix bug in batch mode cli where the first argument is being ignored.
return -1 when a cli command fails.
parse onecmd differently for commands executed over ssh.
support uvisible flag for snapshots from cli.