[plt-scheme] bug in pop3.scm ?

Hi there,

I think there might be a bug in the pop3 collection. The issue is with 
the following function, used to send commands to a POP server:

(define send-to-server
    (lambda (communicator message-template . rest)
      (apply fprintf (communicator-sender communicator)
         (string-append message-template "~n") ;; <----- ~n results in LF
         rest)))

The POP3 RFC specifies that each command should be terminated with CR + 
LF (ASCII 13, ASCII 10) . On Windows "~n" produces a LF only. Some POP 
servers do not like this. Changing the ~n above to \r\n seems to work.

-pp