Although 'register-services' is exported its counterpart 'deregister-service' is not.
Some notes: * 'register-services' is in its plural form while its counterpart is not, maybe one of them should be renamed for consistency sake? * From the docstring and code the interface of 'deregister-service' seems to differ from 'register-services' though I haven't confirmed it. Perhaps add some documented examples for reference? -- Furthermore, I consider that nonfree software must be eradicated. Cheers, Bruno.
