Now that the program starts to have more configuration settings,
it's a good time to create an Options struct and pass that along
down the line so I don't need to pass multiple arguments and
the future development of adding new configurations will become
way nicer.

There's no reason to create the stats HashMap in print_stats anymore
but rather create it in count_stats and return from there.

Separating message crafting from printing makes it possible to be
unit tested.

Wrote those tests too.