The PreProcessedBlock is intended to be a somewhat munged/mogrified form
of a CBlock which is somewhat ready for a db insert.
This data will get passed onto the Controller thread which will set
everything up to commit the SH history, header, etc to the db.
Did some initial testing and it's pretty fast and also.. I think it's
correct (as in I'm collating the data correctly).
TODO: Some more testing.