Links to other READMEs and pkg.go.dev

What's Changed

• links from index to types and functions
• links from functions and types to imported types
  • to other readme files if in same repo
  • to go.pkg.dev if not part of same package
• build instructions into main README

New Contributors

• @jylitalo made their first contribution in #1

Full Changelog: v0.1...v0.2