Use the normal suite run directory for "cylc submit" tasks.
Merge pull request #809 from hjoliver/submit-command-mod

Use the normal suite run directory for "cylc submit" tasks.
Replace sys.exits with raises.
Use fsync on state dump

This ensures that the state dump files would be on disk. Otherwise, with
a busy suite on the ext4 file system, they may be left as zero size
files on a power failure.
Merge pull request #813 from matthewrmshin/fsync-state-dump

Use fsync on state dump
Merge pull request #812 from arjclark/fix.hang-on-empty-state-file

cylc-restart: fix getting stuck on loading broken state file