Bring argument parsing (e.g. `clap`) to `no-std` constrained targets

I work for a medical device manufacturer on safety/life-critical products. I've been developing in Rust for many years now. Before then I developed in C/C++/Go. I was more a std guy until I came back to my first love few months ago, saying embedded systems.

I was quite frustrated that I haven't find a argument parser or a shell crate for no-std targets yet. So, I decided to give it a try and got a first working implementation.

So, I am happy to present to the Rust community an early work on argument parsing for constrained targets : https://github.com/inthehack/noshell ;-).

This is still a work in progress but it actually works for some use cases now.

I tried to make it as hardly tested as possible but this certainly could be better for sure.

I am still working on it to reach a first 1.0.0 release but I would love to have feedback from the community. So feel free to comment, give it a star or fork it.

Stay tuned ;-) !