Add --append option to replay.py.

httparchive.py

 #!/usr/bin/env python
 # Copyright 2010 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
@@ skipping 39 matching lines @@
 
 
 class HttpArchiveException(Exception):
   """Base class for all exceptions in httparchive."""
   pass
 
 
 class HttpArchive(dict, persistentmixin.PersistentMixin):
   """Dict with ArchivedHttpRequest keys and ArchivedHttpResponse values.
 
-  PersistentMixin adds CreateNew(filename), Load(filename), and Persist().
+  PersistentMixin adds the following methods:
+    AssertWritable(filename)
+    Load(filename)
+    Persist(filename)
 
   Attributes:
     server_rtt: dict of {hostname, server rtt in milliseconds}
   """
 
   def __init__(self):
     self.server_rtt = {}
 
   def get_server_rtt(self, server):
     """Retrieves the round trip time (rtt) to the server
@@ skipping 660 matching lines @@
   elif command == 'edit':
     http_archive.edit(options.command, options.host, options.path)
     http_archive.Persist(replay_file)
   else:
     option_parser.error('Unknown command "%s"' % command)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())