metomi/rose#13: rose suite-run: Rose/Cylc version.

Export Rose and Cylc version in `rose suite-run`.
* As environment variable.
* As Jinja2 variable.
* Document in `log/rose-suite-run.conf`.
* (--reload mode should export version of current run, but this is not yet handled.)
metomi/rose#13: rose.run: extend new mode check.

Fail if new mode is specified with reload/restart run mode.
rose suite-run --reload: export old Cylc version.
metomi/rose#13: move version getter logic.
metomi/rose#13: rose.control: get engine version.

"rose suite-gcontrol" and "rose suite-shutdown" will now determine the
engine version of the running suite in a single method.
Merge branch 'master' into 13.rose-version
Merge branch 'master' into 13.rose-version
Merge branch 'master' into 13.rose-version
Update doc/rose-version.js

Warn ourselves that the version line can be evaluated by a shell script.
Merge pull request #350 from matthewrmshin/13.rose-version

rose suite-run: export Rose and suite engine versions