Pyrolite serialization and de-serialization support for HpccRow

The pyspark features wants objects that implement the Pyrolite serialization and de-serialization framework.

At this point, it appears that the best approach will be to replace HpccRow with the GenericRowWithSchema.  We need to make certain that GenericRowWithSchema is stable and intended for external use.  There is an internal version of Generic Row with Schema, so it is very likely that GenericRowWithSchema is intended for external use.