Bug 155493 [Deploy] Pictures and chart pictures are lost when preview on Weblogic Server using WAR deploy
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
* URL parameter name that gives the bookmark expression.
	 */
	public static final String PARAM_BOOKMARK = "__bookmark"; 
	/**
	 * URL parameter name that gives that image rtl option.
	 */
	public static final String PARAM_RTL = "__rtl"; 
	/**
	 * URL parameter name that gives the preview max rows option.
	 */
	public static final String PARAM_MAXROWS = "__maxrows"; 
	/**
	 * URL parameter name that gives the reportlet id.
	 */
	public static final String PARAM_INSTANCEID = "__instanceid"; 
	/**
	 * URL parameter name to indicate whether need to run a reportlet.
	 */
	public static final String PARAM_ISREPORTLET = "__isreportlet";
	/**
	 * Indentify the display text of select parameter
	 */
	protected static final String PREFIX_DISPLAY_TEXT = "__isdisplay__";
	/**
	 * URL parameter name to indicate the resource folder of all the report
	 * resources.
	 */
	public static final String PARAM_RESOURCE_FOLDER = "__resourceFolder"; 
	/**
	 * Custom request headers to identify the request is a normal HTTP request