GitBook development seems a bit stuck right now so let's switch to VuePress which, IMO, is more user friendly. Update the documentation to include the version number in which features were added and use custom container to display notes and warnings.
Split the root README.md in multiple Markdown files (in the `docs/` folder) to make easier reading, editing and extending the documentation. An online version is also available on netlify (https://qtpromise.netlify.com). Building it requires Node.js installed, then:
- npm install -g gitbook-cli
- gitbook install ./
- gitbook build . dist/docs
