If we want to make bar charts selectable (when clicking on a
bar select the dives the bar represents), then we must store
the dives behind bars. Therefore, use dive-based bins instead
of count based bins in bar charts and pie charts. This gave
some churn because every structure where a count is stored
has to be changed to store a vector of dives. Try to use
move semantics where possible to avoid duplication of dive
lists.
On a positive note, the count_dives() function of the
binners can now be removed, since it is unused.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
18a5b5b593