* Test for batching ACL.
* Batch events from sync within BanList.
* Introduce the BanList.batch event to the BanList emitter to let Mjolnir sync after new events have been added from sync.
Fixes#203
The reason for doing this is because otherwise there may be duplicate
rules under different state types for the same entity.
This simplifies the process of modifying or invalidating rules affecting
an entity because the rule with the most recent type will always be
preferred.