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
pptOutput.write( ( "Content-Type: image/"
				+ (String) imageExtensions.get( imagekey ) + "\n\n" ).getBytes( ) );
	}
	private void generateImageBytes( String imageURI ) throws IOException
	{
		exportImageHeader( imageURI );
		Base64 base = new Base64( );
		URL imageURL = null;
		if ( reportDesign != null )
		{
			imageURL = reportDesign.findResource( imageURI,
					IResourceLocator.IMAGE );
		}
		
		
		if ( imageURL == null )
		{
			return;
		}
		if ( imageURL.toString( ).toLowerCase( ).endsWith( ".svg" ) ) 
		{
			
			JPEGTranscoder transcoder = new JPEGTranscoder( );
			
			transcoder.addTranscodingHint( JPEGTranscoder.KEY_QUALITY,
					new Float( .8 ) );
			TranscoderInput input = new TranscoderInput( imageURL.toString( ) );
			
			ByteArrayOutputStream ostream = new ByteArrayOutputStream( );
			TranscoderOutput output = new TranscoderOutput( ostream );