def login(user, password)
      send_command("LOGIN", user, password)
    end
Sends a LOGIN command to identify the client and carries
the plaintext +password+ authenticating this +user+.  Note
that, unlike calling #authenticate() with an +auth_type+
of "LOGIN", #login() does *not* use the login authenticator.

A Net::IMAP::NoResponseError is raised if authentication fails.