Implement AttrDef_Class.

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@157 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/Definition.php

@@ -237,6 +237,7 @@ class HTMLPurifier_Definition
         $this->info_global_attr = array(
             // core attrs
             'id' => new HTMLPurifier_AttrDef_ID(),
+            'class' => new HTMLPurifier_AttrDef_Class(),
             // i18n
             'dir' => new HTMLPurifier_AttrDef_Enum(array('ltr','rtl'), false),
             );