[1.1 / Royalty] Toxic fallout limited to colony

[Wanderer_joins]

This one is not strictly a bug, and is old, but since we now have toxic spewers w/ area of effect, it feels all the more cheesy to be able to form a caravan to have your animals graze on the next tile when there's a toxic fallout.

I'd love to see a random patch of tiles affected by the toxic fallout around the colony or at least a minimal radius around the colony.