ContactList: make sure blocked contacts aren't normally on the contact list
ContactList: make sure blocked contacts aren't normally on the contact list

As per IRC discussion with Sjoerd.

- publish is the result of multiple factors if necessary, so blocked XMPP
  contacts should get publish=No even if they have subscription="both"
- contacts in user-defined groups don't necessarily appear in GCLA()
  (although in XMPP, they would)
- contacts with user-defined aliases don't necessarily appear in GCLA()
  (although in XMPP, they normally would)

freedesktop-unofficial-mirror/telepathy__telepathy-spec,TelepathyIM/telepathy-spec