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
* Returns a new object of class '<em>Needle</em>'.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @return a new object of class '<em>Needle</em>'.
	 * @generated
	 */
	Needle createNeedle( );
	/**
	 * Returns a new object of class '<em>Scale</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Scale</em>'.
	 * @generated
	 */
	Scale createScale( );
	/**
	 * Returns a new object of class '<em>Series</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Series</em>'.
	 * @generated
	 */
	Series createSeries( );
	/**
	 * Returns the package supported by this factory.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the package supported by this factory.
	 * @generated
	 */
	ComponentPackage getComponentPackage( );
}