Wood logs & block to ash, 1 plant: 3 medicine vs 2:5 rebalance

Wood blocks/planks to coke does not have a 20% chance of producing ash.

Instead, player has to choose whether they want coke, or ash from planks.  Similar to wood oven.

Also has the option of burning wood log to 3 ash.

Also changed 2:5 ratio of plants to medicine to 1:3.