Bug 122423 Support page range in RenderTask
Support page range in render task. For PDF format, simply log a message saying range is not supported if a range is specified, and still output whole report. For HTML format, support page range in the form of "1,2,5-10" + "All". The code should check if there is range set. If so, parse it and form a range and output them one after another, with a page splitter in between just like the runAndRenderTask. If no range is set, check if page number is set. There can only be one page in case a page number is set. Invalid page number should be logged, and error message is returned. If neither is set, we default to all pages, instead of the current behavior of giving an error message.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/IRenderTask.java
{
	/**
	 * set the rendering options
	 * 
	 * @param settings
	 *            the rendering options
	 */
	public abstract void setRenderOption( IRenderOption options );
	/**
	 * @return the render option
	 */
	public abstract IRenderOption getRenderOption( );
	/**
	 * sets a specific emitter to use when generate output. Used when there 
	 * are more than one emitters that support a single format. One example 
	 * is the FO-based PDF emitter and the new PDF emitter added in BIRT2.0.
	 * If this function is not called when there are more than 1 emitters 
	 * that support a format, engine may arbitrarily pick one.
	 * @param id the identifier for the emitter
	 */
	public abstract void setEmitterID(String id);
	/**
	 * set the callback function that the engine calls to allow the caller 
     * to have a final change on the report design before running the report
     * @param dm design modifier, which allows the design to be modified 
     * before running the report. Not supported now
     */