Validate, reinstall and apply changes to a workflow.

Validate and reinstall a workflow then either:

• "Reload" the workflow (if it is running),
• or "play" it (if it is stopped).

Currently, if the workflow is running and no source changes are detected, cylc vr aborts with:

WARNING - No changes to source: No reinstall or reload required.

That's fine, because a reload would achieve absolutely nothing.

However if the workflow is stopped and no source changes are detected, we get:

WARNING - No changes to source: No reinstall or play required.

IMO the "no play required" bit is wrong, it should restart the workflow. I wouldn't do cylc vr if I didn't want the workflow to be running. Maybe I don't recall if if I installed my latest changes already, so I do cylc vr instead of cylc play just in case.