Bug 199360 Provide new servlet to retrieve html fragment when in reportlet mode
Currently in reportlet mode, the framesset servlet will still wrap and return all ajax viewer code. We need a new servlet to return only html fragment generated by engine. Then this fragment can be further parsed by client side according to user's requirement.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/servlet/BirtEngineServlet.java
return new BirtContext( request, response );
	}
	/**
	 * Local authentication.
	 * 
	 * @param request
	 *            incoming http request
	 * @param response
	 *            http response
	 * @return
	 */
	protected boolean __authenticate( HttpServletRequest request,
			HttpServletResponse response )
	{
		return true;
	}
	/**
	 * Local do get.
	 */
	protected void __doGet( IContext context ) throws ServletException,
			IOException, BirtException
	{
		ViewerAttributeBean bean = (ViewerAttributeBean) context.getBean( );
		assert bean != null;
		if ( ( IBirtConstants.SERVLET_PATH_PREVIEW.equalsIgnoreCase( context
				.getRequest( ).getServletPath( ) ) || IBirtConstants.SERVLET_PATH_DOCUMENT
				.equalsIgnoreCase( context.getRequest( ).getServletPath( ) ) )
				&& bean.isShowParameterPage( ) )
		{
			requester.service( context.getRequest( ), context.getResponse( ) );