[signals] add signals

fixtracks/utils/signals.py

@@ -15,6 +15,9 @@ class DetectionViewSignals(QObject):
 class DetectionSceneSignals(QObject):
     itemsSelected = Signal(list)
 
+class DetectionTimelineSignals(QObject):
+    windowMoved = Signal((float, float))
+
 class DetectionSignals(QObject):
     hover = Signal((int, QPointF))
     clicked = Signal((int, QPointF))