Fix CanvasItem.draw_set_transform to act according to docs, fixes #2487

scene/2d/canvas_item.cpp

@@ -773,7 +773,7 @@ void CanvasItem::draw_set_transform(const Point2& p_offset, float p_rot, const S
 
 	Matrix32 xform(p_rot,p_offset);
 	xform.scale_basis(p_scale);
-	VisualServer::get_singleton()->canvas_item_set_transform(canvas_item,xform);
+	VisualServer::get_singleton()->canvas_item_add_set_transform(canvas_item,xform);
 }
 
 void CanvasItem::draw_polygon(const Vector<Point2>& p_points, const Vector<Color>& p_colors,const Vector<Point2>& p_uvs, Ref<Texture> p_texture) {