message: gltfpack: Move usage to terminal output
  Instead of documenting usage in the comments, document it in the usage
  text that shows when gltfpack is ran with no arguments.
diff: // contains a work-in-progress loader - please note that the extension specification isn't ready yet so the format
  // will change!
  //
  -// Usage:
  -// gltfpack [options] input output
  -//
  -// Options:
  -// -vpN: use N-bit quantization for position (default: 14; N should be between 1 and 16)
  -// -vtN: use N-bit quantization for texture corodinates (default: 12; N should be between 1 and 16)
  -// -c: produced packed glb files
  -//
  // gltfpack currently supports materials, meshes, nodes and skinning data
  // gltfpack doesn't support morph targets, animation data, lights and cameras
  @@ -1295,13 +1287,18 @@ int main(int argc, char** argv)
  if (argc < 3)
  {
  fprintf(stderr, "Usage: gltfpack [options] input output\n");
  + fprintf(stderr, "\n");
  + fprintf(stderr, "Options:\n");
  + fprintf(stderr, "-vpN: use N-bit quantization for position (default: 14; N should be between 1 and 16)\n");
  + fprintf(stderr, "-vtN: use N-bit quantization for texture corodinates (default: 12; N should be between 1 and 16)\n");
  + fprintf(stderr, "-c: produce compressed glb files\n");
  +
  return 1;
  }
  Settings settings = {};
  settings.pos_bits = 14;
  settings.uv_bits = 12;
  - settings.compress = false;
  for (int i = 1; i < argc - 2; ++i)
  {
  