Bug 148755 Add tthe status to the ActivityStackEvent.
If the the event rollback, the ActivityStackEvent status should be ROLL_BACK.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/activity/ActivityStackEvent.java
/**
	 * One record is executed or one transaction is committed.
	 */
	public final static int DONE = 1;
	/**
	 * The latest record or transaction is redone.
	 */
	public final static int REDONE = 2;
	/**
	 * The latest record or transaction is undone.
	 */
	public final static int UNDONE = 3;
	/**
	 * The activity stack which changes.
	 */
	private ActivityStack stack = null;
	/**
	 * Identifies what action causes this event.
	 */
	private int action;
	/**
	 * Constructs with the stack that changes and the action causing this event.
	 * 
	 * @param theStack
	 *            the stack that changes
	 * @param theAction
	 *            the action causing this event
	 */
	public ActivityStackEvent( ActivityStack theStack, int theAction )
	{