Ran initial Nikola configuration using 'nikola init uw-py-users'.
Updated configuration options to match a website-style site (vs. the default blog-style site).
Added index page and meeting ideas.
Add files generated by `nikola build` to .gitignore.
Added post for July 21 meeting.
Update to use ipython theme.
Added example ipython notebook, `Python Introduction`.
Minor idea updates.
Updated README with installation and usage instructions.