Fix for ticket #477. Use nl2br method when rendering comment::text and

item::description.  In addition add p::clean or p::purify to places that
xss cleaning had missed (i.e. rss feeds)

modules/notification/views/comment_published.html.php

@@ -8,7 +8,7 @@
     <table>
       <tr>
         <td><?= t("Comment:") ?></td>
-        <td><?= p::purify($comment->text) ?></td>
+  <td><?= nl2br(p::purify($comment->text)) ?></td>
       </tr>
       <tr>
         <td><?= t("Author Name:") ?></td>