Basic pluto test of transport mode.

This time behind a NAT, (see transport-01)

A single transport mode SA is created between north and east, for port 3.
On north, firewalling makes sure that one can only access port 3 via IPsec.

inetd is started on east, listening on port 2 and 3, spitting out some stuff.
This is tested with 'telnet | wc'.