TODO for Jabber:

- implement support for transports/agents
- support all message types (chat/ticker/etc)
- add a button for server defaults
- port dialogs to KDialogBase
- support different icons for contacts from servers with broken connections etc.
- show (i.e. with a QToolTip) the subscription status: both, to, from
- add "querying..." feedback while waiting for vCard
- clean up class names in the ui directory, no real scheme there right now
- if a contact subscribed to you, it is being added as a real contact,
  should either be added as temporary or not at all
- ask if authorization should be removed if a contact is deleted from the
  list
- ask the same for added contacts
- provide better feedback for dialogs querying the server
- support avatars and idle times for tooltips
- when trying to register an account, try to display the actual server error
  message
- clean up JabberAddContactPage (needs rewrite)
- support advanced auth methods
- subclass TLS to make use of KDE classes
- allow SSL fallback with setOptProbe
- support account deletion
- factor out client backend to single class JabberClient
- make vCard dialog better, maybe use KIMProxy somehow
- allow fetching vCard from "auth user?" dialog
- allow adding file transfer reasons
- support resuming
