[noise] PSK2 test vectors

[Jonathan Rudenberg]

> On Nov 16, 2015, at 5:40 PM, Alex <alex at centromere.net> wrote:
> 
> Attached are test vectors for the NoisePSK_*_25519_ChaChaPoly_SHA256
> family of handshakes. These were generated by cacophony and verified
> by screech[1].

My psk branch now has a vector generator and a bunch of new ones in the same format as yours. I’ve also added your vectors to my test suite and they all match: https://github.com/titanous/noise/tree/psk