Bug 165188 logging per report
Setting up a dedicated (birt) report server, which serves all our web apps, leads to a logging desaster. Birtegine logs all messages to one file. There's no info which rptdesign caused the logmessage or who (e.g. user) caused the logmessage. Retrieving who/which rpt caused some logmessage is not possible! There are two possible solutions: (a) prefixing each logmessage with a userdefineable message (task.setLogprefix("myprefix")) (b) set an outputstream for each task (task.setLoggingOutputStream(outputstream)) to split the huge logfile to many small pieces.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/ReportEngine.java
* @throws EngineException
	 */
	public IReportRunnable openReportDesign( ReportDesignHandle designHandle )
			throws EngineException
	{
		logger.log( Level.FINE,
				"ReportEngine.openReportDesign: designHandle={0} ", designHandle );
		return helper.openReportDesign( designHandle );
	}
	/**
	 * opens a report design stream and creates a report design runnable. From
	 * the ReportRunnable object, embedded images and parameter definitions can
	 * be retrieved. Constructing an engine task requires a report design
	 * runnableobject.
	 * 
	 * @param designStream
	 *            the report design input stream
	 * @return a report design runnable object
	 * @throws EngineException
	 *             throwed when the input stream is null, or the stream does not
	 *             yield a valid report design
	 */
	public IReportRunnable openReportDesign( InputStream designStream )
			throws EngineException
	{
		logger.log( Level.FINE,
				"ReportEngine.openReportDesign: designStream={0} ", designStream );
		return helper.openReportDesign( designStream );
	}
	public IReportRunnable openReportDesign( String name,