Bug 152828 Add the projectFolder property on module
When user doesn't set the resource folder path in designer, there should be a default working path for Birt to manage the report design and find the related resources. A new property should be added on Module: name: projectFolder type:URL This property only can be given from the open design method from session but should not be set after the module initialized. Concern about the backward compatiblity issue, a new method will be added. Open design with a config argument.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
* @param resourceKey
	 *            Resource key of the user defined message.
	 * @param locale
	 *            locale of message, if the input <code>locale</code> is
	 *            <code>null</code>, the locale for the current thread will
	 *            be used instead.
	 * @return the corresponding locale-dependent messages. Return
	 *         <code>null</code> if resoueceKey is blank.
	 */
	public String getMessage( String resourceKey, ULocale locale )
	{
		return getModule( ).getMessage( resourceKey, locale );
	}
	/**
	 * Return a list of user-defined message keys. The list contained resource
	 * keys defined in the report itself and the keys defined in the referenced
	 * message files for the current thread's locale. The list returned contains
	 * no duplicate keys.
	 * 
	 * @return a list of user-defined message keys.
	 */
	public List getMessageKeys( )
	{
		return getModule( ).getMessageKeys( );
	}
	/**
	 * Returns a slot handle to work with the top-level parameters and parameter
	 * groups within the report. The order that the items appear within the slot
	 * determines the order in which they appear in the "requester" UI.
	 *