Sorry, but this version uses a diferent file-save structure, so it won't be compatible with your old saves...

Considerable optimizations:
- Instead of storing and loading from/into a single large .json file, the plugin now stores each shelf on a separate .json file, the name of which already contains coordinate and world information. I think it should be more eficient this way, + it also makes it even more human readable, and you can delete or edit shelves directly from each of their files if you're up to it.
- Uses Spigot's new 1.14 Player.openBook() method, reducing the code size considerably.

Internal JSON IO operations are now asynchronous, to the benefit of server performance boosting, when interacting with RPGShelves.