prepare for open source release

[jdugan1024]

• add LICENSE
• add docs/PULL_REQUEST_TEMPLATE.md
• add docs/CONTRIBUTING.md
• review / update README
• rename master -> main
• improve docs
• test examples
• setup CI to do linting checks
• add tests
• create NPM project
• add CI/CD to build and publish on tag
• tag first release

[jdugan1024]

This work is being done in the prep-for-release branch.

[jdugan1024]

Used this for CONTRIBUTING.md: https://gist.github.com/PurpleBooth/b24679402957c63ec426

[jdugan1024]

Used this for PULL_REQUEST_TEMPLATE.md: https://raw.githubusercontent.com/embeddedartistry/templates/master/.github/PULL_REQUEST_TEMPLATE.md