Twiddle v2.0.0-alpha.0

• Add chicklets and links to README.md. Closes #39.
• Convert README.md to Markdown. See #39.
• Update .gitignore. See #39.
• Add .npmignore. See #39.
• Build with Actions, ship coverage to Codecov. Closes #37. Closes #38.
• Build with only Node.js 12 on Travis CI. Closes #40.
• Convert to async/await. Closes #36.
• Update LICENSE for 2020. Closes #35.
• Use build utilities in PATH.
• Do not build with Node.js 4 on Travis CI.
• Do not build with Node.js 0.12 on Travis CI.
• Do not build with Node.js 10 on Travis CI.
• Use shorthand repository URL.
• Update LICENSE date range for 2018.
• Upgrade proof to 3.0.x.
• Build with Node.js 8 on Travis CI.ush
• Do not build with Node.js 5 on Travis CI.
• Add Wiseguy to .gitignore.
• Tidy .gitignore.
• Upgrade Proof to 1.2.x.
• Update LICENSE for 2017.
• Plain text README.
• Upgrade to Proof Redux.
• Further indent package.json.
• Get rid of test sub-directory.
• Tidy package.json.
• Build with latest Node.js 6 on Travis CI.
• Build with latest Node.js 6 on Travis CI.
• Pin dependencies to minor version.
• Indent package.json.

Closes #41.