[noise] Snow 0.6 released

[Jake McGinty]

I just pushed the 0.6 release for snow, a Rust implementation of Noise:

* Now WASM-friendly.

* Removed the "Session" type in favor of directly interacting with the
  HandshakeState and TransportState/StatelessTransportState.

* Removed some dependencies, specifically the crusty "rust-crypto"
  behemoth.

A big thank you to all who contributed code to this release!

https://github.com/mcginty/snow/releases/tag/v0.6.0


P.S.: For the next major release, I'm planning on migrating snow to a
zero-allocation library with the help of Rust 2018's new procedural
macros (to maintain aesthetic simplicity). If anyone has opinions on
this design, get in touch :).