Decoupling fullscreen behavior from the generalized border logic
increases the complexity and also inherently changes the behavior in a
way that is not neccesarily desirable. People in IRC notably were
confused about the window controls not being shown in fullscreen because
of this change. We could default the option to yes, but then there will
likely be people confused as to why they suddenly now have the controls
when it wasn't there previously. The best way to avoid all this is just
undo it. If someone wants special fullscreen behavior with
windowcontrols, this can be done with auto profiles already. There's not
much utility in having a separate option.
This reverts commit 3b66428152.