MATLAB class wrapper for a C++ implementation of a Quadtree

This implementation is based on the paper:

S. F. Frisken and R. N. Perry,
``Simple and Efficient Traversal Methods for Quadtrees and Octrees,''
Journal of Graphics Tools, 2002, Vol. 7, pg. 1-11

This Quadtree class seems to beat MATLAB's KDTree class for speed, both in creating the tree and when doing k-nearest neighbor searches.

Note: it is possible to extend this code to an Octree.