Added fix to DocumentImpl that showed problems when the DocumentImpl(conn)
constructor was called. Now there is a new constructor:
DocumentImpl(Connection, String, boolean)
where the boolean value is used to determine if the nodeset should be
read a t the time the cosntructor is called. if false, then
nodeRecordList will be null. Later calls to "toXml()" and other methods
that use nodeRecordList now make sure it is non-null before using it.
So, even if the nodeRecordList isn't read in by the constructor, the toXml()
method will still work as expected.
Changed the "getDocumentInfo(String) method to private scope because there
is now no reason for it to be called outside of the class.
Updated DBQuery and RelationHandler to utilize these changes.