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
* 
	 * @throws PropertyValueException
	 */
	private void removeIncludeCss( String fileName ) throws SemanticException
	{
		if ( fileName == null )
			return;
		
		
		IncludedCssStyleSheet css = getIncludedCssStyleSheetByLocation( fileName );
		if ( css == null )
		{
			throw new CssException( module, new String[]{fileName},
					CssException.DESIGN_EXCEPTION_CSS_NOT_FOUND );
		}
		ElementPropertyDefn propDefn = element
				.getPropertyDefn( IReportDesignModel.CSSES_PROP );
		ComplexPropertyCommand propCommand = new ComplexPropertyCommand(
				module, element );
		propCommand.removeItem( new CachedMemberRef( propDefn ), css );
	}
	/**
	 * Gets css style sheet
	 * 
	 * @param location
	 *            file name
	 * @return css style sheet.
	 */
	private CssStyleSheet getCssStyleSheetByLocation( String location )
	{