added formulae mode to browser
added formulae mode to browser

iCasa/js-xlsx,kaktus40/js-xlsx,kaktus40/js-xlsx,iCasa/js-xlsx,SheetJS/js-xlsx,kaktus40/js-xlsx,thien-thach/searchFromExcel,SheetJS/js-xlsx,thien-thach/searchFromExcel,SheetJS/js-xlsx,iCasa/js-xlsx,iCasa/js-xlsx,SheetJS/js-xlsx,kaktus40/js-xlsx