Bug 180249 BPS39 - Centralized Chart Engine API
Centralized and clearer Engine API -Create one single entry point class ChartEngine in an api package so it's easy to find (with access to IGenerator, Serializer, Device Renderers) -Create a new IGenerator interface instead of exposing the Generator class.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/factory/Generator.java
{
	/**
	 * Internally used.
	 */
	private static final int UNDEFINED = IConstants.UNDEFINED;
	/**
	 * Internally used.
	 */