scikits.ann part deux

I've updated our Python wraper for David Mount and Sunil Arya's Approximate Nearest Neighbor (ANN) library. It now handles searching the tree for the k-nearest neighbors of a set of points. Since it's all done in C, this should be much faster than looping in Python for large sets of points. Along the way, I was able to clean up the API significantly--I got rid of the SWIG-isms and the whole thing feels much more Pythonic now.

If you need to do k-nearest neighbor searches, have a look. It's in the scikits SVN.