Experimental hard-coded three-pane layout

Experimental hard-coded three-pane layout

I'm not happy with it, but it looks good and works better than the
alternatives I've looked at so far.

So why not happy? It's not configurable, and gtk really doesn't do a
great job with the case of notebook widgets that are shrunk to be
smaller than the contents (the cut-off gets ugly, and is outside the
notebook page!)

But committing as a way to keep track of this, and let Dirk use it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>