docstring cleanup and class reference simplification

[mattsb42-aws]

Description of changes:
When I started going through the rendered docs, I realized that Sphinx does not require the full namespace path for custom classes if those classes are defined in this codebase. In light of that, this replaces all of those full namespace paths with just the class name. This results in a much cleaner, more concise, rendered result that still links to the docs for that class.

Note about the change in conf.py: this is just updating the template that I had started with to a more modern syntax for intersphinx_mapping.
http://www.sphinx-doc.org/en/1.5.1/ext/intersphinx.html#confval-intersphinx_mapping

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.