r13829: From the "It's not pretty but it works" category

r13829: From the "It's not pretty but it works" category

* Finish prototype of the "add port command" implementation
  Format is "addportcommand portname deviceURI"

* DeviceURI is either
  - socket://hostname:port/
  - lpr://hostname/queue
  depending on what the client sent in the request
(This used to be commit 6d74de7a676b71e83a3c3714743e6380c04e4425)