Includes generating boards, loading existing boards, and searching for words

Requires a words file in the root of the repo, where each line is a word.

(This project was written on a flight, so it strictly uses what I could remember from the standard library; no 3rd party deps. Being written on a flight also means it's a bit haphazard -- some of the naming + design could certainly be improved, and would have been if the person in front of me hadn't leaned their seat back, taking away precious comfort and typing space!!)