`KDNode.dist` returns squared distance while `search_nn_dist` requires euclidean distance

[MichaelSuen-thePointer]

The two lines below, one requires dist to be euclidean distance, and the other requires it to be squared distance: https://github.com/stefankoegl/kdtree/blob/master/kdtree.py#L501 https://github.com/stefankoegl/kdtree/blob/master/kdtree.py#L508

And the best argument is not used https://github.com/stefankoegl/kdtree/blob/master/kdtree.py#L517