DBDocumentList - Can't take substring of zero-length string. Closes #34

PGDocumentList - Completed fix for serial PK insertion, refactored as best
as could be for now. See #27
Merge branch 'master' of https://github.com/robconery/biggy into newMaster
SQLDocumentList - Fix AddRange method of SQLDocumentList to handle records with auto-generated int PK. Closes #35