rose suite-run -i: gcontrol only if suite running.

In install-only mode, launch gcontrol only if suite is running.
rose suite-run --no-gcontrol -i: document.

Document new behaviour.
rose suite-run -i: launch gcontrol @ correct host.

It was launching gcontrol @ an incorrect host for a running suite.
Merge pull request #426 from matthewrmshin/403.rose-suite-run--install-only.gcontrol

rose suite run: --install only: launch gcontrol only if suite is running
Fixes #403