this = Interface instance
function handleGroup(self, group, width, maxColumns) {
  if (group.length === 0) {
    return;
  }
  var minRows = Math.ceil(group.length / maxColumns);
  for (var row = 0; row < minRows; row++) {
    for (var col = 0; col < maxColumns; col++) {
      var idx = row * maxColumns + col;
      if (idx >= group.length) {
        break;
      }
      var item = group[idx];
      self._writeToOutput(item);
      if (col < maxColumns - 1) {
        for (var s = 0; s < width - item.length; s++) {
          self._writeToOutput(' ');
        }
      }
    }
    self._writeToOutput('\r\n');
  }
  self._writeToOutput('\r\n');
}