message: Dump node values during PrintNodes visitor
  This could come in really handy.
diff: @@ -29,11 +29,36 @@ namespace ospray::sg {
  // Inlined definitions //////////////////////////////////////////////////////
  +#define PRINT_AS(node, type) \
  + if (node.subType() == #type) \
  + std::cout << " [" << node.valueAs<type>() << "]";
  +
  inline bool PrintNodes::operator()(Node &node, TraversalContext &ctx)
  {
  for (int i = 0; i < ctx.level; i++)
  std::cout << " ";
  - std::cout << node.name() << " : " << node.subType() << '\n';
  + std::cout << node.name() << " : " << node.subType();
  +
  + using string = std::string;
  + PRINT_AS(node, string);
  + PRINT_AS(node, bool);
  + PRINT_AS(node, float);
  + PRINT_AS(node, vec2f);
  + PRINT_AS(node, vec3f);
  + PRINT_AS(node, vec4f);
  + PRINT_AS(node, int);
  + PRINT_AS(node, vec2i);
  + PRINT_AS(node, vec3i);
  + PRINT_AS(node, vec4i);
  + PRINT_AS(node, void *);
  + PRINT_AS(node, box3f);
  + PRINT_AS(node, box3i);
  + PRINT_AS(node, range1f);
  + PRINT_AS(node, rgb);
  + PRINT_AS(node, rgba);
  + PRINT_AS(node, affine3f);
  + std::cout << std::endl;
  +
  return true;
  }
  