added headlight option to settings,

added cullface option to settings,
zoom speed now adjust at settings,
bugs:
cullface does not work anymore,
todo:
connect headlight

QtMeshViewer/Header/SettingsWindow.h

@@ -30,4 +30,6 @@ signals:
 	void updateLightColor(QVector3D value);
 	void updateAttFac(double value);
 	void updateAmbCoef(double value);
+	void sendBackfaceCulling(bool value);
+	void sendZommSpeed(int percent);
 };