Bug 174872 Clean up chart model
The chart model contains unused attributes and components. Those just make it difficult to understand the model architecture, so they should be removed from the schema, and the EMF classes must re-generated. Examples are: ChartPreferences, Rule. We need to analyze the model to find out all unused ones. Note that this should not break backward compatibility, otherwise just make them deprecated.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/component/ComponentFactory.java
DialRegion createDialRegion( );
	/**
	 * Returns a new object of class '<em>Grid</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Grid</em>'.
	 * @generated
	 */
	Grid createGrid( );
	/**
	 * Returns a new object of class '<em>Label</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Label</em>'.
	 * @generated
	 */
	Label createLabel( );
	/**
	 * Returns a new object of class '<em>Marker Line</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Marker Line</em>'.
	 * @generated
	 */
	MarkerLine createMarkerLine( );
	/**
	 * Returns a new object of class '<em>Marker Range</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Marker Range</em>'.
	 * @generated
	 */
	MarkerRange createMarkerRange( );
	/**