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
String eNS_URI = "http://www.birt.eclipse.org/ChartModelLayout"; 
	/**
	 * The package namespace name.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	String eNS_PREFIX = "layout"; 
	/**
	 * The singleton instance of the package.
	 * <!-- begin-user-doc --> <!--
	 * end-user-doc -->
	 * @generated
	 */
	LayoutPackage eINSTANCE = org.eclipse.birt.chart.model.layout.impl.LayoutPackageImpl.init( );
	/**
	 * The meta object id for the '{@link org.eclipse.birt.chart.model.layout.impl.BlockImpl <em>Block</em>}' class.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @see org.eclipse.birt.chart.model.layout.impl.BlockImpl
	 * @see org.eclipse.birt.chart.model.layout.impl.LayoutPackageImpl#getBlock()
	 * @generated
	 */
	int BLOCK = 0;
	/**
	 * The feature id for the '<em><b>Children</b></em>' containment reference list.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	int BLOCK__CHILDREN = 0;
	/**