message: gltfio: Fix animator crash for orphaned nodes.
  Fixes
diff: @@ -188,7 +188,20 @@ Animator::Animator(FFilamentAsset* asset, FFilamentInstance* instance) {
  const Sampler* samplers = dst.samplers.data();
  for (cgltf_size j = 0, nchans = srcAnim.channels_count; j < nchans; ++j) {
  const cgltf_animation_channel& srcChannel = srcChannels[j];
  - utils::Entity targetEntity = nodeMap.at(srcChannel.target_node);
  + auto iter = nodeMap.find(srcChannel.target_node);
  + if (iter == nodeMap.end()) {
  + slog.w << "No scene root contains node ";
  + if (srcChannel.target_node->name) {
  + slog.w << "'" << srcChannel.target_node->name << "' ";
  + }
  + slog.w << "for animation ";
  + if (srcAnim.name) {
  + slog.w << "'" << srcAnim.name << "' ";
  + }
  + slog.w << "in channel " << j << io::endl;
  + continue;
  + }
  + utils::Entity targetEntity = iter.value();
  Channel dstChannel;
  dstChannel.sourceData = samplers + (srcChannel.sampler - srcSamplers);
  dstChannel.targetEntity = targetEntity;
  