message: gltfpack: Add instanced triangle counter to verbose output
  This allows us to confirm that the scene complexity doesn't change
  significantly during packing.
diff: @@ -75,6 +75,7 @@ static void printMeshStats(const std::vector<Mesh>& meshes, const char* name)
  {
  size_t triangles = 0;
  size_t vertices = 0;
  + size_t instanced = 0;
  for (size_t i = 0; i < meshes.size(); ++i)
  {
  @@ -82,9 +83,11 @@ static void printMeshStats(const std::vector<Mesh>& meshes, const char* name)
  triangles += mesh.indices.size() / 3;
  vertices += mesh.streams.empty() ? 0 : mesh.streams[0].data.size();
  +
  + instanced += mesh.indices.size() / 3 * std::max(size_t(1), mesh.nodes.size());
  }
  - printf("%s: %d triangles, %d vertices\n", name, int(triangles), int(vertices));
  + printf("%s: %d triangles (%lld instanced), %d vertices\n", name, int(triangles), (long long)instanced, int(vertices));
  }
  static void printSceneStats(const std::vector<BufferView>& views, const std::vector<Mesh>& meshes, size_t node_offset, size_t mesh_offset, size_t material_offset, size_t json_size, size_t bin_size)
  