Fix slugify method to work with Python 2.7.

Add a unit test for the method.
Fix handling of negative indexes in span map
Support restless 2.0 API

There were a few changes made to the restless API when
version 2.0 dropped.  Update the code to reflect this.
See http://restless.readthedocs.org/en/latest/releasenotes/v2.0.0.html

Also add a projects endpoint.