fixed the light problem,

very basic light at the moment, needs a lot of work:
- custom position,
- custom intensities,
- calculate at better positions,
others:
- adjust zoom speed

QtMeshViewer/Header/OglViewerWidget.h

@@ -39,7 +39,7 @@ private:
 
 	struct {
 		QVector3D position = { 1,1,1 };
-		QVector3D intensities = { 1,1,1 };
+		QVector3D intensities = { 1,0.25,0.25 };
 	} m_light;
 
 	QOpenGLShaderProgram m_program;