Fix small issues (mostly substitutions) in cookiecutter template

Mostly these are glitches in the substitutions attributable to the confusion between author_name and full_name - you probably won't notice these if you have a .cookiecutterrc file set up that provides a value for full_name.  However, since the cookiecutter.json file uses author_name (and this is the clearer and less ambiguous form, also used in @pydanny's cookiecutter-django template) I have standardized on that.

I did also extend the substitutions to include the docs/conf.py for Sphinx.

These also fix the README title to reflect the new name, and provide a tests.rst file that was missing (perhaps due to a .gitignore match for tests?).

Thanks for this useful template, for when pydanny's bleeding edge Django template is overkill.