Bug 150347 Support binary stream as preview image.
See 144843. We need model to save binary strame as report preview image. Currently, preview image is an external image. Maybe need a type to distinguish preview image type.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/activity/NotificationEvent.java
/**
	 * The event type of ContentEvent.
	 */
	public static final int CONTENT_EVENT = 0;
	/**
	 * The event type of ElementDeletedEvent.
	 */
	public static final int ELEMENT_DELETE_EVENT = 1;
	/**
	 * The event type of ExtendsEvent.
	 */
	public static final int EXTENDS_EVENT = 2;
	/**
	 * The event type of NameEvent.
	 */
	public static final int NAME_EVENT = 3;
	/**
	 * The event type of NameSpaceEvent.
	 */
	public static final int NAME_SPACE_EVENT = 4;
	/**
	 * The event type of PrpertyEvent.
	 */
	public static final int PROPERTY_EVENT = 5;
	/**
	 * The event type of StyleEvent.
	 */
	public static final int STYLE_EVENT = 6;
	/**
	 * The event type of UserPropertyEvent.