Add support for asynchronous lighting writing and improve aborting
This version includes changes targeted towards the new 1.15.2-v2 BKCommonLib release that allows writing lighting data to the server asynchronously, reducing overhead and fixing some internal server errors that occurred spuriously while fixing.
Updating BKCommonLib to 1.15.2-v2 will also fix a problem of the server crashing when running low on memory, because of a bug in the world saving function since Minecraft 1.14. It is strongly recommended to update.
The abort command now aborts instantly and no longer causes a short freeze.
A side-effect of these changes is that a bug was fixed that the new chunk lighting information was not sent to the nearby players reliably.