* A process pool. When you've stored a function in LiSE, you can `submit` it
to `Engine.pool.submit(..)` using the standard Python
`concurrent.futures.Executor` API. The worker processes all have read-only
views on the state of the simulation.
* Trigger functions now run in parallel by default. Set the `workers` option
to 0 to disable this.
* Neighborhoods. If your rule only runs when something changes near the Thing
or Place it runs on, you can indicate this by setting the rule's
neighborhood property to an integer, and your sim will run faster.
See "Getting started" in the README for an example.
* ELiDE once again updates its graphics in response to events in the LiSE core
-- set the "_image_paths" of a `Thing` or `Place` object to a list of
paths.