First part of the BufferTreeModel pimpification (maybe I should get of

First part of the BufferTreeModel pimpification (maybe I should get of
the "tree" in it's name... can't see/write it anymore :p).
 - The basic structure of the model has been improved.
 - NetworkInfos and IrcChannel objects are now connected to the model
    which allows pretty nice stuff. (we got a working topic yeahi!)

to be continued...