Damage from a given individual or group only counts towards a kill for 10 minutes since that individual or group's last damage to the entity - after this period their damage contribution is removed. This avoids the list of damage contributors growing excessively large for an entity that does a lot of combat but never dies.
EXP sharing within groups is unchanged - the difference is simply that the input to this calculation may be less than 100% of the base EXP reward for the kill if other individuals or groups contributed damage.
This results in an extremely visually noticeable improvement in latency
when adding or removing sprite data and makes the game feel more
responsive.
This happens, for instance, when picking up a sprite like an apple or
flower from the environment. We check to make sure that for items
with lighting (like Velorite) or changes that otherwise affect meshing
(like changing from fluid to nonfluid) this doesn't trigger.
instead just use the same threadpool for everything
helps with debugging problems with GDB
using threadpool.install() to also be used when `into_par_iter()` is called
