Food Slot should consume food when buff or food item expires

Currently, the food slot will only consume food when your hunger level is low enough to need it. This is great if you're only eating meat, say. But when you have multiple foods which provide high amounts of food (from, say, the biofuel stove), that simply won't ever trigger.

I think it would be far more useful if the food slot consumed a food item under any of the following circumstances:

1. You are hungry enough to need that food (existing behaviour)
2. The buff from that food slot is about to expire / has just expired
3. The food item is about to expire

This means that we could permanently keep up a single buff as long as we regularly replenish the food slot. It would also make it work with the Tier 3 food items that spoil before the buff expires (which is otherwise very annoying to micro-manage, and often results in wasted food).