Desktop does not use mark_divelist_changed() anymore - all is done
via the undo machinery. Therefore move this function (and its
counterpart unsaved_changes()) to qmlmanager.cpp.
Ultimately, it probably should be removed from there as well, but
currently I don't dare to touch all the cloud-logic!
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
3358bff432