* serv_smtp.c: when authenticated, do not log out when a RSET command is

* serv_smtp.c: when authenticated, do not log out when a RSET command is
  issued.  This breaks clients which carelessly issue RSET before each
  message, such as Pine.
* serv_smtp.c: when authenticated, ignore envelope FROM:<xxx> sender name
  and replace with address of user who authenticated.  Also fixes Pine.
* serv_smtp.c: when authenticated, not only do we continue our glorious
  RFC-violating condition of replacing the From: header with the user who
  is logged in, but we also stamp it with their preferred Internet address
  for outbound mail (which is kept in CC->cs_inet_email).