Fixed "cylc db refresh" command.

Broken by the recent change to the reg db format - it would abort
if a suite title had been changed. The fix also handles all allowed
quoting forms properly.
Merge branch 'master' into fix-reg-db-refresh
Added refresh to the reg db tests.
Merge pull request #782 from hjoliver/fix-reg-db-refresh

Fixed "cylc db refresh" command.