Bug 194371 Use page emitter framework to implement ppt emitter.
In order to keep consistent with pdf and postscript, ppt need to use page emitter framework.
engine/org.eclipse.birt.report.engine.emitter.ppt/src/org/eclipse/birt/report/engine/emitter/ppt/PPTRender.java
private List currentImageContents = new ArrayList( );
	/**
	 * Returns the output format, always is "ppt".
	 * 
	 * @return the output format
	 */
	public String getOutputFormat( )
	{
		return "ppt";
	}
	/**
	 * Initializes the PPTEmitter.
	 * 
	 * @param services
	 *            the emitter svervices object.
	 */
	public void initialize( IEmitterServices services )
	{
		this.services = services;
		this.reportRunnable = services.getReportRunnable( );
		if ( reportRunnable != null )
		{
			reportDesign = (ReportDesignHandle) reportRunnable.getDesignHandle( );
		}
		this.context = services.getReportContext( );
		Object fd = services.getOption( RenderOption.OUTPUT_FILE_NAME );
		File file = null;
		try
		{
			if ( fd != null )