[noise] rev32b (Release Candidate)

[Jason A. Donenfeld]

This is implemented in WireGuard [1]. Jonathan has just merged the PR
[2] to include this in noise-go. That implementation interops with
WireGuard [3]. As part of the work on [2], I modified the vector
generator to produce many more combinations of handshakes. I encourage
other implementations to verify this 2.1MB file [4].

[1] https://git.zx2c4.com/WireGuard/tree/src/noise.c
[2] https://github.com/flynn/noise/pull/11
[3] https://git.zx2c4.com/WireGuard/tree/contrib/external-tests/go/main.go
[4] https://raw.githubusercontent.com/flynn/noise/master/vectors.txt