Spreadsheet with VCF modifications. Current features include * Support for named and indexed colors in custom formatting rules and formulae via modified Apache POI classes. This feature is intended to be added to mainline Spreadsheet and Apache POI, but is initially provided through VCF. * Vastly improved processing speed for SpreasheetFilterTables, aka. AutoFilter groups. This feature will be included in future releases of Vaadin Flow Components, but is provided ahead of time via Vaadin Component Factory.