Manually replace sort box with fSelect

<link href="path/to/fSelect.css" rel="stylesheet" type="text/css">
<script src="path/to/fSelect.js">
<script>
(function($) {
  $(document).on('facetwp-loaded', function() {
    $('.facetwp-sort-select').fSelect();
  });
})(jQuery);
</script>