training: improve
training: tidy
training: improve sentence
training: fix case
training: better example
training: implement feedback
training: nice image
Handle null string remote host.

The format returned by `cylc get-config` means that null strings may not
be handled correctly. This change should improve it some what.
Merge pull request #513 from matthewrmshin/remote-host-is-null-string

Handle null string remote host.
doc: fix versions.py reference
doc: fix wrong name
doc: fix directory ambiguity
Merge pull request #517 from benfitzpatrick/doc.feedback

rose documentation: implement more feedback and bug fixes
rose suite-log-view -f: handle empty host.
doc: fix
Merge pull request #512 from benfitzpatrick/training.feedback

rose training: additional feedback
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.