Revert "remove htmlpurifier"

This reverts commit c21a462d52.

lib/htmlpurifier/library/HTMLPurifier.func.php

@@ -0,0 +1,23 @@
+<?php
+
+/**
+ * @file
+ * Defines a function wrapper for HTML Purifier for quick use.
+ * @note ''HTMLPurifier()'' is NOT the same as ''new HTMLPurifier()''
+ */
+
+/**
+ * Purify HTML.
+ * @param $html String HTML to purify
+ * @param $config Configuration to use, can be any value accepted by
+ *        HTMLPurifier_Config::create()
+ */
+function HTMLPurifier($html, $config = null) {
+    static $purifier = false;
+    if (!$purifier) {
+        $purifier = new HTMLPurifier();
+    }
+    return $purifier->purify($html, $config);
+}
+
+// vim: et sw=4 sts=4