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
assert theAction == DONE || theAction == REDONE || theAction == UNDONE;
		stack = theStack;
		action = theAction;
	}
	/**
	 * Returns the action which causes this event. The possible value is:
	 * <p>
	 * <ul>
	 * <li><code>DONE</code>
	 * <li><code>REDONE</code>
	 * <li><code>UNDONE</code>
	 * </ul>
	 * 
	 * @return the action which causes this event.
	 */
	public int getAction( )
	{
		return action;
	}
	/**
	 * Returns the stack that changes.
	 * 
	 * @return the stack that changes
	 */
	public ActivityStack getStack( )
	{
		return stack;
	}
}