Minimalistic HTM indexing implementation.

This software is based on work by A. Szalay, T. Budavari, G. Fekete at
The Johns Hopkins University, and Jim Gray, Microsoft Research. See
the following links for more information:

http://voservices.net/spherical/
http://adsabs.harvard.edu/abs/2010PASP..122.1375B

authors: Serge Monkewitz, Walter Landry

Tinyhtm is distributed under a 3 clause BSD-style license.  See
LICENSE.txt for details.