message: Include new AliMCSpectraWeightsHandler in LinkDef
diff: #pragma link C++ class AliTLorentzVector+;
  #if ROOT_VERSION_CODE > ROOT_VERSION(6,4,0)
  #pragma link C++ class AliMCSpectraWeights+;
  +#pragma link C++ class AliMCSpectraWeightsHandler+;
  #pragma link C++ namespace YAML+;
  #pragma link C++ class YAML::Node+;
  #endif
  