Scent cleanup only

I removed all the problematic changes I had made to scentmap updating. This is only the cosmetic changes. I tried to cherrypick the commits, but I kept making mistakes in the merge conflicts, so I just redid them completely.

Biggest changes are now adding the scentmap_{min,max}{x,y} constants, no longer comparing bools to bools, and renaming the two flag caching matrices, in that order.

I should have separated out the complicated changes in the beginning, sorry about that.