[lemoda] Flood-fill game solver updated

[Ben Bullock]

I've updated the solver for the flood game at

https://www.lemoda.net/javascript/flood-it/game.html

The new solver also includes a rough measure of how difficult the board is, which is displayed in the status section of the page. The current solver can solve about 99% of random games. I'm not sure whether all games are soluble. The solutions can vary from one time to another due to some internal conflicts.