Bug 124067 When select the XML file, the relative path should be supported.
Description: When select the XML file, the relative path should be supported. Step to reproduce: 1. new a report 2. new a datasource and dataset based on a XML file 3. select the XML file, the file relative path should be used. Actual result: only the absolute path is supported. Expect result: the relative and absolute path are supported.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/adapter/ModelDteApiAdapter.java
if ( dataSource instanceof ScriptDataSourceHandle )
			return newScriptDataSource( ( ScriptDataSourceHandle ) dataSource );
		
		assert false;
		return null;
	}
	/**
	 * Adapts the specified Model Data Set to a Data Engine API data set design
	 * object
	 */
	public IBaseDataSetDesign createDataSetDesign( DataSetHandle dataSet )
			throws BirtException
	{
		if ( dataSet instanceof OdaDataSetHandle )
			return newExtendedDataSet( ( OdaDataSetHandle ) dataSet,
					context );
		if ( dataSet instanceof ScriptDataSetHandle )
			return newScriptDataSet( ( ScriptDataSetHandle ) dataSet,
					context );
		
		assert false;
		return null;
	}
	/**
	 * Evaluates a property binding Javascript expression
	 */
	String evaluatePropertyBindingExpr( String expr ) throws BirtException
	{
		Object result = JavascriptEvalUtil.evaluateScript( null, jsScope, expr,
				"property binding", 0 );