Description:
------------
mailparse 2.1.1

When parsing an e-mail where there are multiple headers with the same name, e.g. multiple Received: headers, only the last one remains in the data structure returned by mailparse_msg_get_part_data($section). All others are lost, because it's a string and not an array. For now I'm using PEAR/Mail/mimeDecode.php, which does return an array if multiple headers with the same name are found, but it's much slower. I'd appreciate it if you could fix this quickly.

Reproduce code:
---------------
$msg = <<<EOD
Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC;
         Sat, 18 Feb 2006 22:58:14 -0800
Received: from 66.178.40.49 by BAY116-DAV8.phx.gbl with DAV;
        Sun, 19 Feb 2006 06:58:13 +0000

test
EOD;

$mail = mailparse_msg_create();
mailparse_msg_parse($mail,$msg);
$struct = mailparse_msg_get_structure($mail);

foreach($struct as $st) {
	$section = mailparse_msg_get_part($mail, $st);
	$info = mailparse_msg_get_part_data($section);
	echo "<pre>\n";
	var_dump($info);
	echo "</pre>\n";
}


Expected result:
----------------
array(11) {
  ["headers"]=>
  array(1) {
    ["received"]=>
    array(2) {
      [0]=>
      string(95) "from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 18 Feb 2006 22:58:14 -0800"
      [1]=>
      string(82) "from 66.178.40.49 by BAY116-DAV8.phx.gbl with DAV; Sun, 19 Feb 2006 06:58:13 +0000"
  }
  ["starting-pos"]=>
  int(0)
...
}

Actual result:
--------------
array(11) {
  ["headers"]=>
  array(1) {
    ["received"]=>
    string(90) "from 66.178.40.49 by BAY116-DAV8.phx.gbl with DAV;         Sun, 19 Feb 2006 06:58:13 +0000"
  }
  ["starting-pos"]=>
  int(0)
...
}