/**
* [dump_array 将数组内容格式化输出]
* @param array $vars [数组]
* @param string $label [分隔符]
* @param boolean $return [是否返回结果]
* @return [type] [description]
*/
function dump_array($vars, $label = '', $return = false) {
  if (ini_get('html_errors')) {
    $content = "<pre>\n";
    if ($label != '') {
      $content .= "<strong>{$label} :</strong>\n";
    }
    $content .= htmlspecialchars(print_r($vars, true));
    $content .= "\n</pre>\n";
  } else {
    $content = $label . " :\n" . print_r($vars, true);
  }
  if ($return) { return $content; }
  echo $content;
  return null;
}