Update readme

Author: mkj

README.md

@@ -5,34 +5,30 @@ embed pretty much anywhere, I'm collecting possible use cases in
 [discussions](https://github.com/mkj/sunset/discussions/1). Don't hesitate to
 suggest something!
 
-**This software is in an early stage. It is suitable for some applications
-but will certainly have API changes**
-
 - `sunset` (this toplevel) is the core SSH implementation. It provides a
   non-async API, runs with `no_std` and no alloc.
 
-- [`sunset-embassy`](embassy) - async SSH client and server library, also
-  `no_std`. This uses [Embassy](https://embassy.dev/) crate but is async
-  executor agnostic.
+- [`sunset-async`](async) - async SSH client and server library, also
+  `no_std` no-alloc. This is async-executor agnostic (using Embassy for mutexes, but works on std too).
 
-- [`embassy/demos`](embassy/demos) has demos with Embassy executor for wifi on a Raspberry Pi
-  [Pico W](embassy/demos/picow) or a
-  [Linux tap device on `std`](embassy/demos/std) running locally.
+- [`demos`](demos) has demos with Embassy executor for wifi on a Raspberry Pi
+  [Pico W](demos/picow) or a
+  [Linux tap device on `std`](demos/std) running locally.
 
   At present the Pico W build is around 150kB binary size
   (plus ~200KB [cyw43](https://github.com/embassy-rs/cyw43/) wifi firmware),
   using about 15kB RAM per concurrent SSH session (max stack size not confirmed).
 
-- [`sunset-async`](async/) adds functionality to use Sunset as a normal SSH client or
+- [`sunset-stdasync`](stdasync/) adds functionality to use Sunset as a normal SSH client or
   server async library in normal Rust (not `no_std`). This uses Tokio or async-std.
 
-  The [examples](async/examples) include a Linux commandline SSH client `sunsetc`.
-  It works as a day-to-day SSH client.
+  The [examples](stdasync/examples) include a Linux commandline SSH client `sunsetc`. It works as a day-to-day SSH client.
 
 ## SSH Features
 
 Working:
 
+- Client and server
 - Shell or command connection
 - Password and public key authentication
 - ed25519 signatures
@@ -44,20 +40,22 @@ Working:
 
 Desirable:
 
+- SFTP
 - TCP forwarding
-- dh-group14 (probably `std`-only, need to investigate crates)
+- Post quantum hybrid key exchange
+- A std server example
 - Perhaps aes256-gcm
 - Perhaps ECDSA, hardware often supports it ahead of ed25519
-- SFTP
 
 ## Rust versions
 
-At present Sunset will build with latest stable (1.75 at time of writing).
+At the time of writing Sunset will build with Rust 1.81. 
+The requirement may increase whenever useful, targetting stable.
 
-## Safety
+## Checks
 
-Sunset uses `forbid(unsafe)`, apart from `sunset-async` which requires `unsafe`
-for Unix interactions.
+Sunset uses `forbid(unsafe)`, apart from `sunset-async` which 
+requires `unsafe` for Unix interactions.
 
 Release builds should not panic, instead returning `Error::bug()`.
 `debug_assert!` is used in some places for invariants during testing or