fix deprecated warning QMatrix QGraphicsView::matrix() const

Use transform() instead

This class was introduced in Qt 4.2.

sources/editor/elementview.cpp

@@ -479,7 +479,7 @@ void ElementView::drawBackground(QPainter *p, const QRectF &r) {
 	p -> drawRect(r);
 		
 	// determine le zoom en cours
-	qreal zoom_factor = matrix().m11();
+	qreal zoom_factor = transform().m11();
 	
 	// choisit la granularite de la grille en fonction du zoom en cours
 	int drawn_x_grid = 1;//scene_ -> xGrid();