Fast KD Tree in javascript, based on Duyn's java version.

  http://robowiki.net/wiki/User:Duyn/kd-tree_Tutorial
  http://en.wikipedia.org/wiki/K-d_tree

Usage:

  var nodes = [
    { data: "A", coords: [1, 2] },
    { data: "B", coords: [4, 5] },
    { data: "C", coords: [9, 10] }
  ];
  var tree = new FastKDTree();
  tree.add_all(nodes);

  var k = 2;
  var query = [2, 2];
  var nearest_points = tree.k_nearest(query, k);

Notes

  - The "data" key in each node can have an arbitrary value
  - "coords" are length N arrays (N constant for a given tree)
  - The tree uses Euclidean distance for finding the k nearest neighbors
  - The search state uses a simple array instead of a heap - there is an optimization here

Contributions welcome!

Thanks,
Ning