fix pos setting

What was really going on is that expanding a smiley modified the string and
reset the match process. Force set pos so it continues on from the expanded
smiley.

IkiWiki/Plugin/smiley.pm

@@ -79,11 +79,12 @@ MATCH:	while (m{(?:^|(?<=\s|>))(\\?)$smiley_regexp(?:(?=\s|<)|$)}g) {
 			substr($_, $spos, length($smiley))=
 				htmllink($params{page}, $params{destpage},
 				         $smileys{$smiley}, linktext => $smiley);
+			pos=$epos+1;
 		}
 
 		# Breaks out at end, otherwise it will scan through again,
 		# replacing de-escaped ones.
-		last unless defined pos;
+		#last unless defined pos;
 	}
 
 	return $_;