Patch from #115

• Update (aspirational) install instructions in README
• Proofread Title: and Description:
• Check that all exported functions have @return and @examples
• Check that Authors@R: includes a copyright holder (role 'cph')
• Check licensing of included files
• Review https://github.com/DavisVaughan/extrachecks

Prepare for release:

• git pull
• usethis::use_github_links()
• urlchecker::url_check()
• devtools::build_readme()
• devtools::check(remote = TRUE, manual = TRUE)
• git push
• Draft blog post

Version numbering:

• usethis::use_version('patch')
• Increment version number

Github Release

• usethis::use_github_release()
• create tag
• create github release
• usethis::use_dev_version(push = TRUE)