Basic support for _command-line_ options `--help` and `--version`.

* release-0.1.2:
  docs(readme): update history section
  chore(package): bump version to 0.1.2
  feat(cli): parse cli opts with "commander"
  chore(deps): add 'commander' module to package.json
  refactor(index.js): assign module to local variable
  style(strict): add 'strict' directive to index.js
  chore(deps): update version notation