WORLDGUARD-2207 - Reported by sk89q

Priority R-trees are much faster than a flat list of regions and it should be used instead.

Comment by sk89q

For those who are curious, priority R-trees are a spatial indexing algorithm that makes it fast to lookup regions that contain a given geometric point. For you, that means that having 3,000 regions isn't a big deal anymore (in theory) because lookup is much quicker than the old method of "look through the list of all regions." While WorldGuard has always had code for indexing with priority R-trees, it was never used because it had a few notable issues. Those appear to be fixed now, however, with the help of a few contributors.