Fix order of alternative parts

mailboxes/CHANGELOG

@@ -64,3 +64,6 @@ Messages with alternate HTML and text bodies are now send with the multipart/alt
 The original sender's email address is now included in the 'wrote' line when replying to or forwarding a message.
 ---- Changes since 1.480 ----
 Mail with HTML and text bodies now uses a multipart/alternative sub-attachment, so that other attachments are shown properly in mail clients like Hotmail and Yahoo.
+---- Changes since 1.490 ----
+Put text/plain alternative body part before text/html, to be compliant with RFC
+2046.

mailboxes/send_mail.cgi

@@ -102,14 +102,14 @@ if ($in{'body'} =~ /\S/) {
 		local @alts = ( $attach[0] );
 		local $mt = "text/plain; charset=$charset";
 		if ($plainbody =~ /[\177-\377]/) {
-			push(@alts,
+			unshift(@alts,
 			  { 'headers' => [ [ 'Content-Type', $mt ],
 					   [ 'Content-Transfer-Encoding',
 					     'quoted-printable' ] ],
 			    'data' => quoted_encode($plainbody) });
 			}
 		else {
-			push(@alts,
+			unshift(@alts,
 			  { 'headers' => [ [ 'Content-Type', $mt ],
 					   [ 'Content-Transfer-Encoding',
 					     '7bit' ] ],