We were using the QGraphicsScene machinery to zoom into the
plot. This not only zoomed into the dive, but into the whole
thing. In general, one couldn't see the axes anymore.
Instead, adjust the range of the time-axis according to the
zoom-level and position.
Of course, the code isn't adapted to that and the result
is comical. The chart features will have to be fixed
one-by-one. Oh joy.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
c09382036f