Include data for Jan 2013 to Dec 2013

This commit mimics d3cd27a52a9ab3ab8e0a71172d04f151e145d1b3.

As before, I did actually go through the tests and verify they're ok.
Update latest date on 'About the data' page
Improve clarity of text on 'About the data'

- 'Fiscal' is now 'Taxpayers'
- 'Cost recovery' is now 'Fees and charges'
Merge pull request #148 from alphagov/update-data-oct-dec-2013

Include data from January 2013 to December 2013