Query matching for searches
@param  {string} query
@param  {HTMLOptionElement} option
@return {bool}
function(query, option) {
  var result = new RegExp(query, "i").exec(option.textContent);
  if (result) {
    return option.textContent.replace(result[0], "<span class='selectr-match'>" + result[0] + "</span>");
  }
  return false;
}