Added HTMLPurifier (http://htmlpurifier.org/) Version 3.3.0

- can be used via html class like: 

        $clean_html = html::purify($html);

- using it now in eTemplate to remove malicious code from html:
  a) when displaying "formatted text"
  b) when "formatted text" get's input by the user

phpgwapi/inc/htmlpurifier/library/HTMLPurifier/HTMLModule/Tidy/XHTML.php

@@ -0,0 +1,17 @@
+<?php
+
+class HTMLPurifier_HTMLModule_Tidy_XHTML extends HTMLPurifier_HTMLModule_Tidy
+{
+
+    public $name = 'Tidy_XHTML';
+    public $defaultLevel = 'medium';
+
+    public function makeFixes() {
+        $r = array();
+        $r['@lang'] = new HTMLPurifier_AttrTransform_Lang();
+        return $r;
+    }
+
+}
+
+// vim: et sw=4 sts=4