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
* @param content
	 *            the target element to be inserted
	 * @return <code>true</code> if this insertion is valid. Otherwise
	 *         <code>false</code>.
	 */
	protected List checkContent( Module module, DesignElement container,
			int slotId, DesignElement content )
	{
		return new ArrayList( );
	}
	/**
	 * Checks whether elements with the given element definition can be inserted
	 * to the slot <code>slotId</code> in another element
	 * <code>container</code>.
	 * 
	 * @param module
	 *            the module
	 * @param container
	 *            the container element
	 * @param slotId
	 *            the slot id of the container element
	 * @param defn
	 *            the element definition
	 * @return <code>true</code> if this insertion is valid. Otherwise
	 *         <code>false</code>.
	 */
	protected List checkContent( Module module, DesignElement container,
			int slotId, IElementDefn defn )
	{
		return new ArrayList( );