Multiple Authentication Credentials

[Lyndon Nerenberg <lyndon@esys.ca>]

Currently nnimap keeps only a single global set of authentication credentials. 
This prevents accessing multiple servers with different usernames. Is anything 
in the works to change this? What would be very nice would be to store credentials 
something like this:

	server -> port -> authmech -> (user . password)

The reason for authmech is to support concurrent authenticated and anonymous 
access to the same server. Also, it should be possible to store more than one 
"username" credential per server/port/authmech pairing.

--lyndon