Update tests and documentation to use test.pipe2.me on default ports.
echo servers: bind to all interfaces; see #13

We can only map ports on the interface that connects to the gateway
(or, in other words, from the network card, that is connectec to the
router ;). Therefore, to be able to test echo servers, we must listen
on the real interface.
Updates CHANGELOG.md
Bumps version number
Updates CHANGELOG.md