rose suite-log-view -f: handle empty host.
rose rug-brief-tour: add automated tests.

This also allows `rose suite-run` and `rose task-run` to be tested
implicitly.
Merge branch 'master' into t/rose-rug-brief-tour
Merge branch 'master' into empty-remote-host
Merge pull request #519 from matthewrmshin/empty-remote-host

rose suite-log-view -f: handle empty host.
rose.suite_engine_procs.cylc: fix None type error.
Merge pull request #520 from matthewrmshin/none-none

rose.suite_engine_procs.cylc: fix None type error.
Merge branch 'master' into t/rose-rug-brief-tour
Merge pull request #518 from matthewrmshin/t/rose-rug-brief-tour

rose rug-brief-tour: add automated tests.