message: gltfpack: Split help into basic and full
  When using -h we still print the full help, but if -i or -o are not
  specified we display a much shorter help snippet.
diff: @@ -858,11 +858,13 @@ int main(int argc, char** argv)
  {
  fprintf(stderr, "gltfpack %s\n", getVersion().c_str());
  fprintf(stderr, "Usage: gltfpack [options] -i input -o output\n");
  +
  + if (help)
  + {
  fprintf(stderr, "\nBasics:\n");
  fprintf(stderr, "\t-i file: input file to process, .obj/.gltf/.glb\n");
  fprintf(stderr, "\t-o file: output file path, .gltf/.glb\n");
  fprintf(stderr, "\t-c: produce compressed gltf/glb files (-cc for higher compression ratio)\n");
  - fprintf(stderr, "\t-v: verbose output (print version when used without other options)\n");
  fprintf(stderr, "\nTextures:\n");
  fprintf(stderr, "\t-te: embed all textures into main buffer\n");
  fprintf(stderr, "\t-tb: convert all textures to Basis Universal format (with basisu executable); will be removed in the future\n");
  @@ -883,8 +885,21 @@ int main(int argc, char** argv)
  fprintf(stderr, "\t-ke: keep extras data\n");
  fprintf(stderr, "\nMiscellaneous:\n");
  fprintf(stderr, "\t-cf: produce compressed gltf/glb files with fallback for loaders that don't support compression\n");
  - fprintf(stderr, "\t-noq: disable quantization\n");
  + fprintf(stderr, "\t-noq: disable quantization; produces much larger glTF files with no extensions\n");
  + fprintf(stderr, "\t-v: verbose output (print version when used without other options)\n");
  fprintf(stderr, "\t-h: display this help and exit\n");
  + }
  + else
  + {
  + fprintf(stderr, "\nBasics:\n");
  + fprintf(stderr, "\t-i file: input file to process, .obj/.gltf/.glb\n");
  + fprintf(stderr, "\t-o file: output file path, .gltf/.glb\n");
  + fprintf(stderr, "\t-c: produce compressed gltf/glb files (-cc for higher compression ratio)\n");
  + fprintf(stderr, "\t-te: embed all textures into main buffer\n");
  + fprintf(stderr, "\t-tc: convert all textures to KTX2 with BasisU supercompression (using basisu executable)\n");
  + fprintf(stderr, "\t-si R: simplify meshes to achieve the ratio R (default: 1; R should be between 0 and 1)\n");
  + fprintf(stderr, "\nRun gltfpack -h to display a full list of options\n");
  + }
  return 1;
  }
  