[1.7.0] Add native support for required elements

- Factored out large portion of ValidateAttributes to AttrValidator
- Implemented ValidateAttributes armor
- Fix clear cache bug
- Implement armoring for ValidateAttributes

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1174 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/Token.php

@@ -13,6 +13,12 @@ class HTMLPurifier_Token {
     var $type; /**< Type of node to bypass <tt>is_a()</tt>. @public */
     var $line; /**< Line number node was on in source document. Null if unknown. @public */
     
+    /**
+     * Lookup array of processing that this token is exempt from.
+     * Currently, the only valid value is "ValidateAttributes".
+     */
+    var $armor = array();
+    
     /**
      * Copies the tag into a new one (clone substitute).
      * @return Copied token