Revert "remove htmlpurifier"

This reverts commit c21a462d52.

lib/htmlpurifier/library/HTMLPurifier/Token/Comment.php

@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Concrete comment token class. Generally will be ignored.
+ */
+class HTMLPurifier_Token_Comment extends HTMLPurifier_Token
+{
+    public $data; /**< Character data within comment. */
+    public $is_whitespace = true;
+    /**
+     * Transparent constructor.
+     *
+     * @param $data String comment data.
+     */
+    public function __construct($data, $line = null, $col = null) {
+        $this->data = $data;
+        $this->line = $line;
+        $this->col  = $col;
+    }
+}
+
+// vim: et sw=4 sts=4