When checking for trip-overlap on import, only really overlapping trips
have been considered, i.e. when dives had overlapping times.
Instead use the TRIP_THRESHOLD so that on download dives are added to
the same trip if in a two-days time frame.
Reported-by: Miika Turkia <miika.turkia@gmail.com>
Reported-by: Dirk Hohndel <dirk@hohndel.org>
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
These functions were spread out over dive.c and divelist.c.
Move them into their own file to make all this a bit less monolithic.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>