Bring README up to date with `master` branch#247

Merged

coltonweaver merged 7 commits intoaws:masterfrom

voteblake:new-release-readme

Jan 29, 2021

Commits on Jul 28, 2020

First pass of changes to bring README up to date with `master` branch,
voteblake
committed
First round of PR feedback - address typos and `extern crate`
voteblake
authored