Bug 201368 Support "Not In" operator in filter list
Description: After we support "IN" filter we should also support the "Not In" filter. Data part has already support the "Not In" filter, so hope model can support that operator in the filter operator list. Regards!
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/CssCommand.java
*            css style sheet
	 * @throws SemanticException
	 *             if failed to add <code>IncludedCssStyleSheet</code>
	 *             strcutre
	 */
	public void addCss( CssStyleSheet sheet ) throws SemanticException
	{
		if ( sheet == null )
		{
			return;
		}
		
		
		String fileName = sheet.getFileName( );
		if ( getCssStyleSheetByLocation( fileName ) != null )
		{
			throw new CssException( module, new String[]{fileName},
					CssException.DESIGN_EXCEPTION_DUPLICATE_CSS );
		}
		ActivityStack activityStack = getActivityStack( );
		activityStack.startTrans( );
		CssRecord record = new CssRecord( module, element, sheet, true );
		getActivityStack( ).execute( record );
		
		try
		{
			IncludedCssStyleSheet css = StructureFactory
					.createIncludedCssStyleSheet( );
			css.setFileName( fileName );
			doAddCss( css );