message: gltfpack: Add -h commandline switch
  Also rename uv_bits to tex_bits in Settings to match command line naming
  better.
diff: @@ -63,9 +63,11 @@ struct Mesh
  struct Settings
  {
  int pos_bits;
  - int uv_bits;
  + int tex_bits;
  +
  int anim_freq;
  bool anim_const;
  +
  bool compress;
  bool verbose;
  };
  @@ -555,7 +557,7 @@ QuantizationParams prepareQuantization(const std::vector<Mesh>& meshes, const Se
  result.pos_scale = std::max(pos_max.f[0] - pos_min.f[0], std::max(pos_max.f[1] - pos_min.f[1], pos_max.f[2] - pos_min.f[2]));
  }
  - result.uv_bits = settings.uv_bits;
  + result.uv_bits = settings.tex_bits;
  Attr uv_min, uv_max;
  if (getAttributeBounds(meshes, cgltf_attribute_type_texcoord, uv_min, uv_max))
  @@ -2202,11 +2204,12 @@ int main(int argc, char** argv)
  {
  Settings settings = {};
  settings.pos_bits = 14;
  - settings.uv_bits = 12;
  + settings.tex_bits = 12;
  settings.anim_freq = 30;
  const char* input = 0;
  const char* output = 0;
  + bool help = false;
  for (int i = 1; i < argc; ++i)
  {
  @@ -2218,7 +2221,7 @@ int main(int argc, char** argv)
  }
  else if (strcmp(arg, "-vt") == 0 && i + 1 < argc && isdigit(argv[i + 1][0]))
  {
  - settings.uv_bits = atoi(argv[++i]);
  + settings.tex_bits = atoi(argv[++i]);
  }
  else if (strcmp(arg, "-af") == 0 && i + 1 < argc && isdigit(argv[i + 1][0]))
  {
  @@ -2244,6 +2247,10 @@ int main(int argc, char** argv)
  {
  settings.verbose = true;
  }
  + else if (strcmp(arg, "-h") == 0)
  + {
  + help = true;
  + }
  else
  {
  fprintf(stderr, "Unrecognized option %s\n", arg);
  @@ -2251,7 +2258,7 @@ int main(int argc, char** argv)
  }
  }
  - if (!input || !output)
  + if (!input || !output || help)
  {
  fprintf(stderr, "Usage: gltfpack [options] -i input -o output\n");
  fprintf(stderr, "\n");
  @@ -2264,6 +2271,7 @@ int main(int argc, char** argv)
  fprintf(stderr, "-ac: keep constant animation tracks even if they don't modify the node transform\n");
  fprintf(stderr, "-c: produce compressed glb files\n");
  fprintf(stderr, "-v: verbose output\n");
  + fprintf(stderr, "-h: display this help and exit\n");
  return 1;
  }
  