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
* message IDs that are defined by the customers. One entry of
	 * <code>Translation</code> represents a translated message for a specific
	 * locale.
	 * <p>
	 * 
	 * @param translation
	 *            new entry of <code>Translation</code> that are to be added
	 *            to the module.
	 */
	public void addTranslation( Translation translation )
	{
		translations.add( translation );
	}
	/**
	 * Drops a Translation from the module.
	 * <p>
	 * 
	 * @param translation
	 *            the translation to be dropped from the module.
	 * 
	 * @return <code>true</code> if the report module contains the given
	 *         translation.
	 */
	public boolean dropTranslation( Translation translation )
	{
		return translations.remove( translation );
	}
	/**
	 * Finds a <code>Translation</code> by the message resource key and the
	 * locale.