Recognize O2 percentage from MacDive import

MacDive use "o2percent" in its XML export

Signed-off-by: Henrik Brautaset Aronsen <subsurface@henrik.synth.no>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
When switching sort order, scroll the dive list to the current dive

Now that we actually seem to understand the whole notion of setting the
active dive, let's take that code a bit further, and always scroll to it
when we're introducing a new sort ordering.

Sure, there may be other selected dives, but we have one primary
(current) dive that we show the profile and dive data for, and when we
switch sort order we probably want to see that dive in the dive list.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>