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
* <p>
	 * Part of: Meta data system.
	 * 
	 * @return The element definition. Will always be non-null in a valid build.
	 */
	public IElementDefn getDefn( )
	{
		if ( cachedDefn == null )
		{
			cachedDefn = MetaDataDictionary.getInstance( ).getElement(
					getElementName( ) );
			assert cachedDefn != null;
		}
		return cachedDefn;
	}
	/**
	 * Adds a user-defined property. The property must be unique within the
	 * inheritance hierarchy of this element. It cannot duplicate either another
	 * user-defined property or a system-defined property. These checks must
	 * have been enforced by the application prior to calling this method.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param userProp
	 *            definition of the user-defined property
	 */
	public void addUserPropertyDefn( UserPropertyDefn userProp )
	{
		assert getDefn( ).allowsUserProperties( );
		assert userProp != null;