message: gltfpack: Filter out negligibly small weights
  Instead of preserving all bone influences during sorting, we now discard
  influences that, when encoded in a quantized 8-bit integer, result in
  weight=0. Validator now warns about 0 influences associated with non-0
  joints, and this fixes the warnings.
diff: @@ -945,6 +945,9 @@ void sortBoneInfluences(Mesh& mesh)
  if (!joints || !weights)
  return;
  + // weights below cutoff can't be represented in quantized 8-bit storage
  + const float weight_cutoff = 0.5f / 255.f;
  +
  size_t vertex_count = mesh.streams[0].data.size();
  for (size_t i = 0; i < vertex_count; ++i)
  @@ -956,7 +959,7 @@ void sortBoneInfluences(Mesh& mesh)
  int count = 0;
  for (int k = 0; k < 4; ++k)
  - if (wa.f[k] > 0.f)
  + if (wa.f[k] > weight_cutoff)
  {
  inf[count].i = ja.f[k];
  inf[count].w = wa.f[k];
  