This was written with massive hand-holding by Tomaz - actually, this was
mostly proposed via IRC by Tomaz and then implemented by me...
Right now because of the list-of-lists nature of the model we have the
small issue that every trip starts with a dark background dive, even if
the trip itself has a dark background.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>