Adds a second material type to most comestibles.
Carnivores can eat dairies!

Confirmed as unintended behavior
Digestion improvements

Carnivores refuse to eat veggies or fruit, but their grain intolerance
is handled in the same way as wheat-allergic characters now. A carnivore
with a bionic-enhanced digestive can still enjoy some spaghetti with
meat sauce.
Fruit-hating characters still hate fruit even with bio-digestion,though.
Merge pull request #6521 from 9600bauds/mats_comest

Adds a secondary material to most comestible items.