tracker/pt, options: fix threshold slider

It's only the tie_setting(slider_value, QSlider) that
has race-free slider updates. Needed to update the
threshold slider representation.

Remove the tie_setting(int, QSlider) overload since it
doesn't have the logic.

Add a migration.

Add base_value::notify() for use-cases like the
checkbox updating the label.

1 files changed, 2 insertions, 0 deletions

diff --git a/tracker-pt/ftnoir_tracker_pt_dialog.h b/tracker-pt/ftnoir_tracker_pt_dialog.h
index 59519601..c1c25fb0 100644
--- a/tracker-pt/ftnoir_tracker_pt_dialog.h
+++ b/tracker-pt/ftnoir_tracker_pt_dialog.h
@@ -38,6 +38,8 @@ public slots:
 signals:
     void poll_tracker_info();
 private:
+    QString threshold_display_text(int threshold_value);
+
     settings_pt s;
     Tracker_PT* tracker;
     QTimer timer, calib_timer;