Currently, setting the visibility of chart features is a mess. It
is done when switching to the profile state and then via signals,
when the preferences are changed.
However, when the preferences are changed the chart is replot anyway.
So let us simply set the visibility on chart replot. Then in
a follow-up commit, the signals can be removed.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
adf6e6d31e