replace NULL with null

Another global search-and-replace update. Here, I've replaced the PHP
keyword 'NULL' with its lowercase version. This is another PEAR code
standards change.

darcs-hash:20081223192129-84dde-4a0182e0ec16a01ad88745ad3e08f7cb501aee0b.gz

_darcs/pristine/lib/personal.php

@@ -32,7 +32,7 @@ class PersonalAction extends Action {
 
     function views_menu() {
 
-        $user = NULL;
+        $user = null;
         $action = $this->trimmed('action');
         $nickname = $this->trimmed('nickname');