UNFINISHED: Fix AIX services

If you get impatient with me putting the final touches on the acceptance tests, go ahead and finish 'em. I can give you hints.

Sprint.ly item:231: Fix service provider to allow enabling and disabling services on AIX

* item:265 Add new commands and common helper methods
* item:230 Allow enabling services
* item:232 Allow disabling services
* item:273 Allow service introspection via self.instances
* item:266 Write spec tests and ...
* Start on accpetance tests