How to use armadillo?

1. Start a new project with RStudio.
2. Open `dev/install_and_test.R` and run it.
3. Open `src`, inspect the OLS function, and start creating your own
   functions.
4. Run `load_all()` as in the script from point 2, and use `install()` to
   install the package locally when you are ready.
5. Add your own README and favourite license with `usethis::use_readme_rmd()`
   and `usethis::use_XYZ_license()`.

See the details at https://github.com/pachadotdev/armadillo.
