Bug 130492 Provide a method to serialize the report with library information.
Currently, when engine generate the report document file, the document does not contain any library information. That will cause many propblem on server side. Model should provide a method to serialize the report with library information to a stream so that the generated report document can contain all information that the report need.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* reference is just a name, but the system has not yet identified the
	 * target structure, or if a target even exists. A resolved reference caches
	 * a pointer to the target structure itself.
	 * 
	 * @param oldRef
	 *            the old reference, if any
	 * @param newRef
	 *            the new reference, if any
	 * @param prop
	 *            definition of the property
	 */
	protected void updateReference( StructRefValue oldRef,
			StructRefValue newRef, ElementPropertyDefn prop )
	{
		ReferencableStructure target;
		
		
		if ( oldRef != null )
		{
			target = oldRef.getTargetStructure( );
			if ( target != null )
				target.dropClient( this );
		}
		
		
		
		if ( newRef != null )
		{
			target = newRef.getTargetStructure( );
			if ( target != null )