Bug with autolinking e-mail addresses with underscores

[Carl-Johan Kihlbom]

I have discovered an unfortunate bug in Markdown. Running an autolinked  
e-mail address with and underscore through Markdown replaces the  
underscore with the (rendered) string  
"b14a7b8059d9c055954c92674ce60032". For example:

$ echo "<a_b at hotmail.com>" | /Markdown.pl
<p><a  
href="&#x6D;&#x61;&#105;&#x6C;&#x74;&#111;:&#97;b&#x31;4&#x61;7&#x62; 
&#x38;&#48;&#x35;&#57;&#100;&#x39;&#99;&#x30;&#53;&#x35;9&#53;&#52; 
&#x63;9&#x32;&#54;&#x37;4&#99;&#101;&#x36;&#48;&#48;3&#x32;&#x62;&#64; 
&#104;&#111;t&#x6D;&#x61;&#105;&#108;&#x2E;&#99;&#111;&#109;">&#97; 
b&#x31;4&#x61;7&#x62;&#x38;&#48;&#x35;&#57;&#100;&#x39;&#99;&#x30;&#53; 
&#x35;9&#53;&#52;&#x63;9&#x32;&#54;&#x37;4&#99;&#101;&#x36;&#48;&#48; 
3&#x32;&#x62;&#64;&#104;&#111;t&#x6D;&#x61;&#105;&#108;&#x2E;&#99; 
&#111;&#109;</a></p>

This translates to:

<p><a  
href="mailto: 
ab14a7b8059d9c055954c92674ce60032b at hotmail.com">ab14a7b8059d9c055954c926 
74ce60032b at hotmail.com</a></p>

I apologise if this has already been discussed. I couldn't find  
anything in the archives.

I hope this can be resolved soon, as I love Markdown! It's a great  
piece of software.

Keep up the good work.

/ Carl-Johan Kihlbom