Journalist v0.1.0

• Unit test coverage of file create. See #54.
• Build with only Node.js 12 on Travis CI. Closes #53.
• Add links and badges to README.md. Closes #47.
• Convert readme file to Markdown. See #47.
• Build with Actions, ship coverage to Codecov. Closes #49. Closes #48.
• Add .npmignore. Closes #52.
• Update LICENSE for 2020. Closes #51.
• Copy existing implementation from Strata. See #47. Closes #50.
• Use GitHub URL shorthand in package.json. See #47.
• Remove old release notes. See #47.
• Upgrade mkdirp to 0.5.1.
• Upgrade mkdirp to 2.5.4.
• Upgrade Proof to 1.2.x.
• Tidy package.json.
• Build on Travis without shipping to web server.
• Remove npm-debug.log.

Closes #55.