Patch from Galen Charlton: The attached patch adds triggers on biblio.record_entry...

Patch from Galen Charlton: The attached patch adds triggers on biblio.record_entry and authority.record_entry to prevent the insertion or update of MARCXML that is not well-formed.  Since the various consumers of bre.marc and are.marc tend not to handle invalid XML all that well, these triggers serve as a (very basic) data integrity check.  libmail.georgialibraries.org/pipermail/open-ils-dev/2010-June/006116.html

git-svn-id: svn://svn.open-ils.org/ILS/trunk@16614 dcc99617-32d9-48b4-a31d-7c20da2025e4