Added options data functionality
Added ability to fetch options data from yahoo! finance. With this there are a few 'helper' methods to get different things out of the data.

Answers issue #1739

Also cleaned up a bit of the /pandas/io/data.py file to comply better with PEP8.

Thanks for this!
 Great functionality! Are there any plans to upgrade to BeautifulSoup4 (bs4) instead of version 3?
 I would happily accept a pull request
