This makes it easier for downstream projects (forks) to replace the
version fetching system with their own. It is as simple as implementing
an interface and overriding the default implementation of
org.bukkit.UnsafeValues#getVersionFetcher()
It also makes it easier for us to organize things like the version
history feature.
Lastly I have updated the paper implementation to check against the site
API rather than against jenkins.
Instead of allocating a buffer for every chunk compression, reuse
the same 64k sized buffer.
Also stopped doing dynamic compression levels. It wasn't helping enough.
This will improve memory usage and zlib performance of chunk compression.
Exposes a mutable array on items a player should keep on death.
This allows a cleaner method to implement "Keep certain items on death"
than how plugins currently do it in that it never removes them in first
place, so its safe if the player logs out/server is shutdown before respawn.
Example Usage: https://gist.github.com/aikar/5bb202de6057a051a950ce1f29feb0b4
