Service cleaner module

The intention of this cleaner is to provide a little more stability than could otherwise be achieved via bash scripts. Since runner likes to retry on errors, then reboot, if we made the mistake of attempting to restart a service on some system where it didn't exist it could cause a tree closure. The '--if-exists' option here removes that worry by simply doing a quick check before attempting to restart a service.

This also opens up the possibility of implementing the same API atop OSX systems.