Make the pane split be vertical rather than horizontal

Ok, this makes that dive list look empty and ugly, but as mentioned, we
really should start filling it with all the useful information that we
can sort by, like temperature and air use.

And even stuff that might not make sense to sort by (would you want to
sort by cylinder size or name? Or by nitrox percentage) could still be
*shown* in the list fairly naturally.

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