Add explanation and example for 'Secure Cookie Handshake' to akka-sample-remote

Added some commented out configuration items to provide an example of how to use
the Secure Cookie Handshake feature. Users can simply uncomment to try it out

Added an indication in the application.conf file that the remote.netty.tcp.port is
actually the LISTEN port.
 #3520 - fixing putLongParts in ByteStringBuilder and adding tests
Fixing dead code in MessageContainerSerializer.scala
Merge pull request #1635 from akka/wip-3520-fix-putLongParts-in-ByteStringBuilder-2.2-√

Wip 3520 fix put long parts in byte string builder 2.2 √
unsubscribeAddressTerminated only if nonlocal watches were installed (issue 3542)
Merge branch 'wip-3542-2.2-no-defensive-unsubscribe' of github.com:octo47/akka into wip-3542-2.2-no-defensive-unsubscribe