Another big update today.

* Mostly finished dialogs for network settings, identities, network list.
* Network settings are also already mostly honored by our TelnetDeluxe the core still is.
  This means that the connect button works, we will connect to the first server we defined
  for this network, and we can also autoconnect. We still don't use identities yet, i.e.
  the nick is still hardcoded.
* Started implementing buffer management in the core. Cleaned up the framework, the core now
  creates server objects for all networks it connects to, and the signals we use to connect
  everything have a format that allows us to use network and buffer names.
* Threw out a lot of the temporary dirty-hack-stuff we used for testing so far. Most of the
  code we have now is actually clean and there to stay, although of course enough is still to
  be added to it :)