Changed the color of the 2D param mesh to the default blue

Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp

@@ -247,7 +247,7 @@ public :
   {
     QPen pen;
     QBrush brush;
-    brush.setColor(Qt::red);
+    brush.setColor(QColor(100, 100, 255));
     brush.setStyle(Qt::SolidPattern);
     pen.setColor(Qt::black);
     pen.setWidth(0);