Fire bukkit chunk load/unload events. Add loadChunkOnProvideRequest configuration option. Revert the reversion to standard unloading. Apparently I actually did fix it, but didn't realise because 4AM logic.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>
Handle the seemingly impossible scenario where a chunk is loaded in the wrong place.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>
Reset chunks if x/z coordinates do not match.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>
Don't repeatedly unload 0,0 chunk, avoid boxing with NonBlockingLongSet.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>