Paper: Scaling Polygon Adjacency Algorithms to Big Data Geospatial Analysis (Jason Laura)

Draft submission.  Changes likely on review of co-author and debugging of the build environment (failing on a fresh Ubuntu 14.04 install + Anaconda + TexLive).
The ``:ref:`twostep` `` is not rendering a label.  I am not certain what the problem is here, perhaps @stefanv has a suggestion?