rem: return stream >> static_cast<Q_UINT8>(sig.mType) >> sig.mUrl >> sig.mText;
add: Q_UINT8 t; stream >> t >> sig.mUrl >> sig.mText; sig.mType = t; return stream;
context: QDataStream & operator>>( QDataStream & stream, Signature & sig ) {  return stream >> static_cast<Q_UINT8>(sig.mType)		>> sig.mUrl		>> sig.mText;}