Implementation of the nokia.contacts localmsg server

In this pull request I'm just using a fake contact, I'll hook up the mozContacts API in another pull request.
There are still a couple of messages not implemented (getFirst and getNext), but they should be trivial now (the hard part was Notify).
There are still a couple of things unclear to me, but I think we can figure them out later when needed.
Erm, I mean "readonly". That's the correct value of the "access" property if you want read-only access to the contacts database.