patch to support strike for MT's markdown

Markdown.pl.patch

--- mt.bk/plugins/Markdown/Markdown.pl	2012-05-10 05:03:28.000000000 -0400
+++ mt/plugins/Markdown/Markdown.pl	2012-08-21 04:29:37.000000000 -0400
@@ -971,6 +971,10 @@
     $text =~ s{ (\*|_) (?=\S) (.+?) (?<=\S) \1 }
         {<em>$2</em>}gsx;
 
+    # These lines added by Bill Eccles, 2008-07-04
+    $text =~ s{ (\s) (~~) (?=\S) (.+?) (?<=\S) (~~) }
+    {$1<strike>$3</strike>}gsx;
+
     return $text;
 }