[noise] Go implementation

[Jason A. Donenfeld]

Hey Jonathan,

My implementation works with your implementation.

Here's the test I've implemented, that works like a charm: [1].
It's the same as the Rust one I did for Screech: [2].
Alex is working on the Haskell one for his implementation.

As was the case of the Rust one, this is the first Go I've ever written.

Jason

[1] http://0bin.net/paste/wcgQ7qXsOkLEfLqE#ROSkM4AptVe25FxjQzdkPdLxWKviWAqIy9M2S+YH629
[2] http://0bin.net/paste/dcAgOKdRHZljfUR1#txue-Vsu3lRyfjENwDCImLFA5B2ZPvBOFNRCbgDlWNZ