-Added CustomCreationConverter -Added IsReference to JsonContainerAttribute -Added PreserveReferencesHandling to JsonSerializer -Added IReferenceResolver to JsonSerializer -Split internals of JsonSerializer into JsonSerializerWriter (serializes) and JsonSerializerReader (deserializes) -Moved serialize stack from JsonWriter (yuck) to JsonSerializerWriter (yay) -Added FromObject overload with JsonSerializer argument for cases when state is needed