gideon: integrated qextmid

[Matthias Hölzer-Klüpfel]

Hi all,

I have commited my changes to gideon, integrating qextmdi as an alternative 
topelvel user interface. Given the popular demand, I have made it the default 
mode. If you want to use the IDEA-like interface, right now you have to put

[UI]
MajorUIMode=sdi

in your gideonrc. I think I will leave this as it is for now. I imagine the 
"Right Thing" with the IDEA-like interface would be to add it as another mode 
to qextmdi, but I guess only Falk can judge (and code ;) this issue 
correctly.

Please note that you need a recent katepart, or you will get segfaults when 
opening text files.

Bye,
Matthias.