Update copyright notice from Swarming to LUCI; add AUTHORS and CONTRIBUTORS.

appengine/swarming/swarming_bot/bot_code/xsrf_client_test.py

 #!/usr/bin/env python
-# Copyright 2013 The Swarming Authors. All rights reserved.
+# Copyright 2013 The LUCI Authors. All rights reserved.
 # Use of this source code is governed by the Apache v2.0 license that can be
 # found in the LICENSE file.
 
 import datetime
 import logging
 import os
 import sys
 import time
 import unittest
 
@@ skipping 110 matching lines @@
     remote = xsrf_client.XsrfRemote(
         'http://localhost/',
         '/swarming/api/v1/bot/handshake')
     remote.xsrf_request_params = {'attributes': 'b'}
     self.assertEqual('foo', remote.url_read('/a', data={'foo': 'bar'}))
 
 
 if __name__ == '__main__':
   logging.basicConfig(level=logging.ERROR)
   unittest.main()