Merge pull request #821 from matthewrmshin/kill-job-process-group

Run at/background jobs in their own process group
Merge pull request #824 from benfitzpatrick/cylc-restart-fail-corrupt-state-dump

cylc restart: fail for corrupt status in state dump
Merge branch 'master' into improve-state-dump

Conflicts:
	bin/cylc-restart
Merge pull request #825 from matthewrmshin/improve-state-dump

Improve suite state dump logic
Updated change log for 5.4.6.
Removed the special 'sequential' task type.
Catch exception on rolling_archive.
Merge pull request #828 from arjclark/fix.quota-exceeded-shutdown

#712: Catch exception on rolling_archive.
Implement pre-initial filtering for task messaging.
Added tests for pre-initial cycle messaging.
Document gcylc symlink in cylc-wrapper.
Reimplemented sequential tasks with inter-cycle triggers.
(Re)Documented sequential tasks.
Merge pull request #832 from hjoliver/gcylc-wrapper

Allow "gcylc" for "cylc gui" with the cylc version wrapper.
Merge pull request #831 from arjclark/fix.pre-init-messages

#827: Pre-initial-cycle triggers are now ignored for message outputs
Fixed some test suites.
Fixed a typo.
Minor coding efficiency improvements (credit M.Shin).
Fixed an error in the suicide tutorial suite.
Warn on suiciding an active task.