Bug#395052: Please provide the GTK frontend with a better handler for BOOLEAN questions

[Attilio Fiandrotti <attilio.fiandrotti@gmail.com>]

One more thing: please evaluate if it's better having the active by 
default radio button focused, so that the user has to move up/down with 
the arrows and then press enter, or if it's better having the focus on 
the inactive button.
I assigned focus to the inactive radio button, so that i can simply 
press spacebar with the thumb and hit enter with the middle finger 
without using the arrow keys, but i'm not sure this is not confusing.

Attilio