Markdown.pl: allow '/' in auto-quoted attribute values

When auto-quoting the attribute value of something like this:

    <a href=http://example.com/test/>test</a>

Do not stop at the first "/", instead pick up the entire value.

Of course, whitespace will still terminate the value being auto-quoted.

Additionally, when checking the end of the tag to see if it's
self-closing (e.g. "<br/>") do not include the final character of
any value that may have been picked up by the auto-quoting process.

For the example above, that prevents the opening "a" tag from
mistakenly being considered self-closing just because the value
being auto-quoted happens to end in a "/" and butts right up against
the final ">" of the tag.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>

Markdown.pl

@@ -3791,7 +3791,7 @@ sub _Sanitize {
 		++$atc;
 		next;
 	    }
-	    if ($tag =~ /\G([^\s<\/>]+)\s*/gcs) {
+	    if ($tag =~ m{\G([^\s<>]+)\s*}gcs) {
 		# auto quote it
 		my $v = $1;
 		$v =~ s/\042/&quot;/go;
@@ -3807,11 +3807,11 @@ sub _Sanitize {
 	$out =~ s/\s+$//;
 	my $typ = 1;
 	if ($tagmt{$tt}) {
-	    $typ = ($tag =~ m,/>$,) ? 3 : -3;
+	    $typ = ($sfx =~ m,/>$,) ? 3 : -3;
 	    $out .= $opt{empty_element_suffix};
 	    return ("&lt;" . substr($tag,1), 0) if !$atc && $taga1p{$tt};
 	} else {
-	    if ($tag =~ m,/>$,) {
+	    if ($sfx =~ m,/>$,) {
 		return ("&lt;" . substr($tag,1), 0) if !$atc && $taga1p{$tt};
 		$typ = 3;
 	    } else {