Replace by custom implementation, with the ultimate goal to
remove the QtCharts module. This doesn't yet display axis
titles or a grid.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Implement a simple scatter series for plotting two numerical variables
agains each other. Since the scatter symbols may overlap, on hover
multiple dives are shown in the information box. If the box
would become too large, only the first few dives are shown followed
by "and X more".
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>