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/XMLCommonAttributes.php

@@ -0,0 +1,14 @@
+<?php
+
+class HTMLPurifier_HTMLModule_XMLCommonAttributes extends HTMLPurifier_HTMLModule
+{
+    public $name = 'XMLCommonAttributes';
+
+    public $attr_collections = array(
+        'Lang' => array(
+            'xml:lang' => 'LanguageCode',
+        )
+    );
+}
+
+// vim: et sw=4 sts=4