Jan Wolter:

 - Think about changing "pipe" to be the default method.  Probably not worth
   the incompatibility that would arrise.

 - Look into developing a "socket" method, in which we first try open a
   socket connecting to the external authenticator, and only launch a new one
   if the initial connection attempt fails.  This would avoid launching a
   new authenticator for each hit.  Instead the authenticator would be a
   persistant process that can hold open a connection to the database and
   even do caching of recent authentications.

 - Allow command line arguements to be passed to the authenticator on the
   AddExternalAuth command.  This way you could use the same authentication
   program to authenticate out of different databases or configuration files.

 - Windows support.  Not something I'm likely to do, but a good idea.

 - Merge with Satoh Fumiyasu's version 3.0.0beta3.
