Method AddNode

src/core/kdtree.hpp:52–63

Create one new node in the tree, return its index in the pool */

	/** Create one new node in the tree, return its index in the pool */
	size_t AddNode(const T &element)
	{
		if (this->free_list.empty()) {
			this->nodes.emplace_back(element);
			return this->nodes.size() - 1;
		} else {
			size_t newidx = this->free_list.back();
			this->free_list.pop_back();
			this->nodes[newidx] = node{ element };
			return newidx;
		}
	}

	/** Find a coordinate value to split a range of elements at */
	template <typename It>