Added Wild Cotton: grows in savannas, drops Cotton Seeds

I like this change. I always thought cotton was too hard to get. Even if you added a mod for creatures to the game, you would rarely encounter enough sheep or spiders to collect enough wool for a bed within the first few days of playing.
And having to spend the night waiting in your fully secured house, that just gets old quickly.

The previous unmodded way of obtaining it, by breaking Jungle Grass, was also not exactly self-explanatory.