The whole edit logic moved from displayed_dive to current_dive
and it became more and more tedious to keep these in sync.
Therefore, simply always display current_dive. The only exceptions
are the equipment tab and the planner, as these are not yet
integrated in the undo system. Once this is done, displayed_dive
can be removed.
Moreover, remove the clear parameter from updateDiveInfo().
Instead simply clear of there is no current_dive set.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>