This one exposes undo/redo as well as some basic trip manipulations, very similar
to what's already available on the dive details page. Except that here it also
makes sense to add a selected dive to a trip above or below (if those exist and
the dive isn't already in a trip).
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
ffdcc8bf30