Initial implementation.
Fix shutdown hang and add to test battery.
Assign correct db as "primary"
#1115: cylc gui graph view: crop proxy points
fix terminology
cylc release: fix regex family bug and add tests
cylc hold: add task and family tests
Merge remote branch 'upstream/master' into cylc6.viewable-db
cylc reload: fix daemon logfile reporting
Merge pull request #1185 from benfitzpatrick/1115.immortal-r1-graph

cylc gui graph view: crop purely-base-node-points
Merge pull request #1191 from benfitzpatrick/fix-reload-logfiles

cylc reload: fix daemon task logfiles reporting
Merge pull request #1190 from benfitzpatrick/release-families-regex-bug

cylc release: fix families regex bug
cylc scan: scan multiple hosts

Scan all monitored hosts by default.
Merge remote branch 'upstream/master' into cylc6.viewable-db
cylc poll: fix submit-fail handling
Back compat.
cylc poll: modify new test to allow submit-fail
Merge pull request #1192 from benfitzpatrick/fix-poll-submit-fail

cylc poll: fix submission failed handling
cylc restart: fix 'runahead' state handling
Merge pull request #1193 from benfitzpatrick/restart-runahead

cylc restart: fix 'runahead' state handling