OpenGL modernization: various fixes

include/gui/glscope.h

@@ -200,6 +200,7 @@ private:
 	void drawPowerOverlay();
 
 protected slots:
+	void cleanup();
 	void tick();
 };
 

include/gui/glspectrum.h

@@ -209,9 +209,8 @@ private:
 	void enterEvent(QEvent* event);
 	void leaveEvent(QEvent* event);
 
-	void cleanup();
-
 private slots:
+	void cleanup();
 	void tick();
 	void channelMarkerChanged();
 	void channelMarkerDestroyed(QObject* object);