[noise] A more idiomatic Rust implementation

[sopium]

Hello folks,

I was trying to implement WireGuard with Rust, but found the screech
implementation quite difficult to work with. Its development is also
quite inactive. So I tried to refactor it, and ended up with a massive
rewrite.

The fork is at [https://github.com/sopium/noise-rust]. It is more
idiomatic and easier to use, at least in my opinion, becuase it:
* uses `Option` instead of `has_something`,
* uses a more straightforward ownership model and static dispatching,
* uses `Vec`,
etc.

There are obviously a lot more needed to be done to form a complete
and good implementation of noise: tests, documentaion, and do not
panic with invalid input, etc.

I would love to complete and maintain it if you think what I have now
it is good start.

Regards,
Sopium