Volume service helper 626

Fixes #626
Also fixes #305 


This factors the `VolumeService` creation and startup out of all of the "scripts" that need that service and puts it into a single `ICommandLineScript` implementation.  This, in turn, passes the initialized service in to the other "scripts" that need it.

 `SystemExit.code`  might be clearer than comparing the general `args` tuple.