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/Transitional.php

@@ -0,0 +1,9 @@
+<?php
+
+class HTMLPurifier_HTMLModule_Tidy_Transitional extends HTMLPurifier_HTMLModule_Tidy_XHTMLAndHTML4
+{
+    public $name = 'Tidy_Transitional';
+    public $defaultLevel = 'heavy';
+}
+
+// vim: et sw=4 sts=4