Fixing date fields in header of `index.html`.

1. Our script requires YYYY-MM-DD (two digits for the day) for start and end dates.
2. The end date was the same as the start date.
3. We prefer 3-letter month abbrevations (like 'Oct') in the human-readable date so that our home page formats nicely.
Merge pull request #1 from gvwilson/gh-pages

Fixing date fields in header of `index.html`.