core_io vs genio vs ciborium-io

This is a copy of libstd::io with all the parts that don't work in core removed. Most importantly, it provides the Read and Write traits. This crate is (mostly) automatically generated from the rust git source. The version of the source that corresponds to your compiler version will be selected automatically by the build script.

A type safe, low level replacement for `std::io`. Supports `no_std` for embedded development, just disable cargo feature `std`. Because of limitations of `std::io::Error` type, `genio` provides `Read` and `Write` traits that allow implementors to choose their own type. This type can be better at expressing what kinds of error can happen.

Simplified Read/Write traits for no_std usage