message: Moved back to [] syntax, works for exisitng string keys now.
diff: @@ -105,8 +105,7 @@ filament::MaterialInstance* MeshReader::MaterialRegistry::getMaterialInstance(
  void MeshReader::MaterialRegistry::registerMaterialInstance(const utils::CString& name,
  filament::MaterialInstance* materialInstance) {
  // Add the material to our map
  - //mImpl->materialMap[name] = materialInstance;
  - mImpl->materialMap.insert({name, materialInstance});
  + mImpl->materialMap[name] = materialInstance;
  }
  void MeshReader::MaterialRegistry::unregisterMaterialInstance(const utils::CString& name) {
  