Add option to disable playing widget

src/widgets/playingwidget.cpp

@@ -156,6 +156,10 @@ void PlayingWidget::SetApplication(Application *app, AlbumCoverChoiceController
 
 }
 
+void PlayingWidget::SetEnabled(bool enabled) {
+  if (enabled) SetEnabled();
+  else SetDisabled();
+}
 
 void PlayingWidget::SetEnabled() {
   enabled_ = true;

src/widgets/playingwidget.h

@@ -67,6 +67,8 @@ class PlayingWidget : public QWidget {
   ~PlayingWidget();
 
   void SetApplication(Application *app, AlbumCoverChoiceController *album_cover_choice_controller);
+  bool IsEnabled() { return enabled_; }
+  void SetEnabled(bool enabled);
   void SetEnabled();
   void SetDisabled();
   void set_ideal_height(int height);