After invalidating the filter, the dive-selection was modified to
ensure that at least one dive is selected. This was done in the
filter code, but it seems preferrable to do this in the dive-list
code, which has direct access to the selection-model.
Therefore, move the code from MultiFilterSortModel to DiveListView.
While doing so, split the code in DiveListView into more functions to:
1) Get the index of the first dive (if any).
2) Select the first dive (if any).
This allows a distinct size reduction of conditional compilation
in MultiFilterSortModel (accesses to MainWindow are not possible
in mobile code).
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
9829e49815