Interval Heap vs MinHeap

I was thinking it was the different heap... but actually turns out the heaps are approximately the same performance, with the difference being the pruning:

 - #1 Rednaxela's kd-tree (3rd gen, Interval Heap) [0.0290]
 - #2 Rednaxela's kd-tree (3rd gen) [0.0290]
 - #3 Rednaxela's kd-tree (3rd gen, Interval Heap, Prune When Points Added) [0.0293]
 - #4 Rednaxela's kd-tree (3rd gen, Interval Heap, Avoid Growing Heap When Possible) [0.0294]
 - #5 Skilgannon's Cache-hit KDTree [0.0296]

So the incremental difference from a larger heap is less than the cost of removing the points.