code: function columnNum(){
          var count;
          var $headerColumns = $header.find(opts.headerCellSelector);
          if(existingColGroup){
            count = $tableColGroup.find('col').length;
          } else {
            count = 0;
            $headerColumns.each(function () {
              count += parseInt(($(this).attr('colspan') || 1), 10);
            });
          }
          if(count !== lastColumnCount){
            lastColumnCount = count;
            var cells = [], cols = [], psuedo = [], content;
            for(var x = 0; x < count; x++){
              content = $headerColumns.eq(x).text();
              cells.push('<th class="floatThead-col" aria-label="'+content+'"/>');
              cols.push('<col/>');
              psuedo.push(
                $('<fthtd>').css({
                  'display': 'table-cell',
                  'height': 0,
                  'width': 'auto'
                })
              );
            }
  
            cols = cols.join('');
            cells = cells.join('');
  
            if(createElements){
              $fthRow.empty();
              $fthRow.append(psuedo);
              $fthCells = $fthRow.find('fthtd');
            }
  
            $sizerRow.html(cells);
            $sizerCells = $sizerRow.find("th");
            if(!existingColGroup){
              $tableColGroup.html(cols);
            }
            $tableCells = $tableColGroup.find('col');
            $floatColGroup.html(cols);
            $headerCells = $floatColGroup.find("col");
  
          }
          return count;
        }
docs: get the number of columns and also rebuild resizer rows if the count is different than the last count