SEC-1023: Add hasPermission() support to SecurityExpressionRoot

http://jira.springframework.org/browse/SEC-1023.

hasPermission() now delegates to a PermissionEvaluator interface, with a default implementation provided by the Acl module. The contacts sample now uses expressions on the ContactManager interface. The permission-evaluator element on global-method-security can be used to set the instance to an AclPermissionEvaluator. If not set, all hasPermission() expressions will evaluate to 'false'.

samples/contacts/src/main/java/sample/contact/PublicIndexController.java

@@ -51,7 +51,7 @@ public class PublicIndexController implements Controller, InitializingBean {
     }
 
     public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)
-        throws ServletException, IOException {
+            throws ServletException, IOException {
         Contact rnd = contactManager.getRandomContact();
 
         return new ModelAndView("hello", "contact", rnd);