For historic reasons, there where three distinct signals concerning
dive-selection from the undo-machinery:
1) divesSelected: sent newly selected dives
2) currentDiveChanged: sent if the current dive changed
3) selectionChanged: sent at the end of a command if either the selection
or the current dive changed
Since now the undo-commands do a full reset of the selection, merge these
three signals into a single signal.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2e230da361