Bug 197228 Need updaet createdBy info when serialize the module
When open module, designer will pass the property map which contains the createdBy info. this info should be retained by moduleHandle and then be updated and written when doing serialization. Note if this info is null, model should not update it during serialization. This could happen for api users or third-party designer. For BIRT designer, it will guarantee this value always not null.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* Identifier for the cube element name space.
	 */
	public static final int CUBE_NAME_SPACE = 8;
	/**
	 * Number of defined name spaces.
	 */
	public static final int NAME_SPACE_COUNT = 9;
	/**
	 * The session that owns this module.
	 */
	protected DesignSession session;
	/**
	 * The number of the next element ID.
	 */
	protected long elementIDCounter = 1;
	/**
	 * The hash map for the id-to-element lookup.
	 */
	protected HashMap idMap = new HashMap( );
	/**
	 * The undo/redo stack for operations on this module.
	 */
	protected ActivityStack activityStack = new ActivityStack( );
	/**
	 * The save state used for dirty file detection. See
	 * {@link org.eclipse.birt.report.model.activity.ActivityStack}for details.
	 */
	protected int saveState = 0;
	/**
	 * Internal table to store a bunch of user-defined messages. One message can