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
return true;
		if ( obj instanceof DesignElementHandle )
			return ( (DesignElementHandle) obj ).getElement( ) == this;
		return false;
	}
	/**
	 * Returns the slot that contains the given content element.
	 * 
	 * @param content
	 *            the element to find
	 * @return the number of the slot that contains the element, or -1 if this
	 *         element does not contain the content element.
	 */
	public int findSlotOf( DesignElement content )
	{
		IElementDefn defn = getDefn( );
		int count = defn.getSlotCount( );
		for ( int i = 0; i < count; i++ )
		{
			if ( getSlot( i ).contains( content ) )
				return i;
		}
		return -1;
	}
	/**
	 * Checks whether the property of current element is editable.
	 * 
	 * @return <code>true</code> if the property of current element is
	 *         editable. Otherwise <code>false</code>.
	 */