-use the second set of GVARs to track adding and removing attributes.
-Epoch_player* vars moved to local vars only accessible inside the
master loop.
-TODO: finish digest system with a config entry to control digest
limits. Some extra logic is needed.
Basically, when you consume some food, it will not increase your hunger
level immediately but raise over time.
Each of these should have limits on how much you can store in the digest
and how much each tick the digest var can affect the local player var in
the master loop.
