[noise] Go implementation

[Jonathan Rudenberg]

I have a basic Go implementation of revision 18 at https://github.com/titanous/noise

No pipes implementation yet and it’s only tested with the vectors from screech. I’m going to implement the proposed PSK spec on a branch to test next.

I might also generate a vector set for each handshake type and crypto algorithm combination.

The spec was really easy to implement in very little code. Great work!

Jonathan