Minor updates resulting from work with MedAllies testing with their HPD

* Added a few .toString() for clearer logging in FINE level when
dumping models
* Renamed two OU constants that were out of sync with the IWG spec
* Made the parseResponseDocToHPDEntities method a little more accepting
of minor casing issues on OU's
* in getNormalizedBatchResponse, made it smarter about pulling out the
<batchResponse> when we know it's wrapped by a SOAP Envelope. The
"HACK" comment is still relevant and reasonable at this point.