eliminate title attribute from xml_documents
The current 'title' attribute in the xml_docuemnts tabe and xml_revisions table
is no longer needed because of the flexible 'returnfield' query mechanism that
allows the query to specify which fields to return. Thus, we need to delete it
from the tabels, and delete all of the mentions of it from the code, including
the DBSAXHandler code that updates this field on insert and update.