[noise] Potential cleanups for a rev35?

[Trevor Perrin]

We'd talked a little about doing a revision 35 soon after 34, just to
cleanup a few things in the text:

https://moderncrypto.org/mail-archive/noise/2018/001535.html
https://moderncrypto.org/mail-archive/noise/2018/001547.html

(1) Integrate PSK into text alongside other tokens, instead of having
it in its own section?

(2) Move security properties tables into appendix, so the main text is
more readable?

It's not completely obvious that those are good cleanups: there are
some things I like about having the PSK discussion self-contained, and
about emphasizing the security tables.

But we could try drafting those and see how they look.


There's a few other cleanups we could consider:

(3) Remove SetNonce() in favor of a cleaner treatment of out-of-order
nonce handling, per recent discussion with Jake, Justin, and Luke.

(4) I'm wondering whether "transport" in "transport phase" is the best
name, since the term "transport" is pretty overloaded in network
protocols.  TLS prefers "traffic" for this phase, we could consider
that?

(5) Our distinction between "handshake phase" and "transport phase"
isn't very explicit that some handshakes rely on the first transport
messages to achieve their full security properties.  Noise Explorer
calls these "tokenless messages".  I wonder if we should do something
cleverer with our terminology and phases here, but not really sure
what...

Anyways, comments on above welcome, or other small text things we
could clean up.

Trevor