Draft: Update to DataPacking for RichMCSegment for thread-safety

The RichMCSegment is one of the 'event model' classes that are filled at the end of Gauss. The packing of this data causes a crash when running Gauss in the new framework in the multi-threaded mode. This update provides a solution to avoid this crash. However, this is only an interim solution which enables one to run Gauss in multi-threaded mode. A longer term solution to this class other similar 'event model' classes for thread-safety are starting to be discussed.