Preliminary addition of hostname to db etc.
Merge remote branch 'upstream/master' into 140-hostname
User@Host working, submit_method working.
code tidy and reorder
Fixed "none" hosts issue.
Merge remote branch 'upstream/master' into 140-hostname

Conflicts:
	lib/cylc/task_types/task.py

Use suite_host to get hostname
Merge remote branch 'upstream/master' into 140-hostname

Conflicts:
	lib/cylc/task_types/task.py
Merge pull request #257 from arjclark/140-hostname

Database of suite events: record user@host and submit method