this could happen if a plugin declared a permission already declared by another plugin, and then declared a different default for it (e.g. true instead of op).
if a chunk was requested for generation, count++ and count(activeRequests)++, which means that we would only get to submit half as many generation requests as we're allowed to.
Calculate the limit at the start and remember it instead.
we don't want to allow sending further chunks when we haven't generated near ones, because we won't be able to see them anyway, and we might end up not needing them.
This now fully matches the results of PM3.
all remaining submodules are now non-essential to running a server.
They are also versioned and updates can be done automatically using 'composer update'.
Finally, we can also put an end to the issue of translations being rendered incorrectly or being missing due to outdated submodules.
this ensures that the edge of loaded terain is always the same distance
away in any direction. This also means that when flying parallel to X or
Z axes, you now have about 12% more chunks directly in front of you,
instead of to your left and right, which gives the impression that
chunks are loading faster (they aren't, they are just being ordered in a
more sensible way).
this fixes the horrible spotty chunk loading seen in https://twitter.com/dktapps/status/1456397007946461190?s=20.
In practice, this made chunks invisible on teleport for several tens of seconds after teleporting. Having a larger chunks-per-tick with large render distance compounded to worsen the problem.
It wasn't really noticeable on small render distances, but very obvious on large ones with fast chunk sending and slow generation.
This also fixes#4187 (at least to the extent that it works on PM3, anyway).
I actually intended to write a tool for debugging generation, but it turns out this, as an intermediary step, is also useful and a whole bunch of fun to play with.
this matches the vanilla behaviour. For some reason it doesn't consider levels (so you can have a level higher or lower than this without actually having that amount of XP), but this matches Java behaviour as of 1.10.
fixes#4543
