Markeen - Smart fill

I just wrote a smarter method of determining the fill order for Markeen. Previously, I already had a method to calculate the probabilities of each tile in a given space. I used that to determine a "diversity of options" for each not-yet-filled tile. Instead of using a predetermined order, the filler now deals with the spaces with less diversity first, since the more diverse ones can presumably accommodate more choices.

I did my best to include some caching, but handling of all those probabilities for every place is expensive. Markeen is at least a hundred times slower now, even after I temporarily disabled the rare structure handling (which is difficult to integrate with the cache updating). The levels seem alright, but this new strategy isn't a magic bullet. I do think there's still more to explore with it; I haven't tried to fine-tune the diversity computer at all.

Here are all ten levels I generated with this new version:

(Click to enlarge.)