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 meta object id for the '{@link org.eclipse.birt.chart.model.layout.impl.ClientAreaImpl <em>Client Area</em>}' class.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @see org.eclipse.birt.chart.model.layout.impl.ClientAreaImpl
	 * @see org.eclipse.birt.chart.model.layout.impl.LayoutPackageImpl#getClientArea()
	 * @generated
	 */
	int CLIENT_AREA = 1;
	/**
	 * The feature id for the '<em><b>Background</b></em>' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int CLIENT_AREA__BACKGROUND = 0;
	/**
	 * The feature id for the '<em><b>Outline</b></em>' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int CLIENT_AREA__OUTLINE = 1;
	/**
	 * The feature id for the '<em><b>Shadow Color</b></em>' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int CLIENT_AREA__SHADOW_COLOR = 2;
	/**