Bug 207268 Add visibility option for plot within axes
For chart with axes, we should make plot within axes invisible. Meantime, other plots, such as axes, legend and title, should be visible. This enhancement doesn't include UI change, and it is required for cross tab integration.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/layout/LayoutPackage.java
/**
	 * The feature id for the '<em><b>Outline</b></em>' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int LEGEND__OUTLINE = BLOCK__OUTLINE;
	/**
	 * The feature id for the '<em><b>Background</b></em>' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int LEGEND__BACKGROUND = BLOCK__BACKGROUND;
	/**
	 * The feature id for the '<em><b>Visible</b></em>' attribute. <!--
	 * begin-user-doc --> <!-- end-user-doc -->
	 * 
	 * @generated
	 * @ordered
	 */
	int LEGEND__VISIBLE = BLOCK__VISIBLE;
	/**
	 * The feature id for the '<em><b>Triggers</b></em>' containment reference list.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int LEGEND__TRIGGERS = BLOCK__TRIGGERS;
	/**