various: moved time from viewer UI to viewer node

app/dialog/export/codec/imagesection.cpp

@@ -47,6 +47,7 @@ ImageSection::ImageSection(QWidget* parent) :
   frame_slider_->SetMinimum(0);
   frame_slider_->SetValue(0);
   frame_slider_->SetDisplayType(RationalSlider::kTime);
+  connect(frame_slider_, &RationalSlider::ValueChanged, this, &ImageSection::TimeChanged);
   layout->addWidget(frame_slider_, row, 1);
 }
 

app/dialog/export/codec/imagesection.h

@@ -59,6 +59,9 @@ public:
     frame_slider_->SetValue(t);
   }
 
+signals:
+  void TimeChanged(const rational &t);
+
 private:
   QCheckBox* image_sequence_checkbox_;