Downloading FOIA contact info for federal agencies

(This is a **work-in-progress** PR, not meant yet for merging.)

I'm downloading agency contact information for FOIA, from the [FOIA.gov request form](http://www.foia.gov/report-makerequest.html). It has a table of contacts:

![foia-1](https://cloud.githubusercontent.com/assets/4592/3290432/2ebd7816-f578-11e3-9548-bccf1be1221e.png)

That when selected, bring you to another dropdown:

![foia-3](https://cloud.githubusercontent.com/assets/4592/3290441/44e235fa-f578-11e3-9a96-0d1cdf9762e1.png)

And when a department is selected, it shows you full contact info:

![foia-4](https://cloud.githubusercontent.com/assets/4592/3290444/4afd2760-f578-11e3-9216-f803d1a9d36e.png)

`contacts.rb` uses the AJAX endpoints behind this process to load contact info, by downloading their HTML to the `html/` directory (unversioned). It then parses the contact details out of them, and makes YAML files in the `data/` directory (versioned).

Data looks like this:

```yaml
---
abbreviation: FCC
name: Federal Communications Commission
description: The Federal Communications Commission (FCC) is an independent United
  States government agency. The FCC was established by the Communications Act of 1934
  and is charged with regulating interstate and international communications by radio,
  television, wire, satellite and cable. The FCC's jurisdiction covers the 50 states,
  the District of Columbia, and U.S. possessions.
departments:
- name: Federal Communications Commission
  address:
  - Vanessa Lamb
  - FOIA Contact
  - Room 1-B135
  - 445 12th Street, SW
  - Washington, DC 20554
  phone: 202-418-0440
  fax: 202-418-0521
  emails:
  - FOIA@fcc.gov
  service_center: 'Phone: (202) 418-0440, (202) 418-0212'
  public_liaison: 'Stephanie Kost, Phone: (202) 418-1379'
  website: http://www.fcc.gov/foia/
  request_form: http://transition.fcc.gov/foia/#reqform
```

More to come before merging.

## Why do this?

The [FOIA.gov developer page](http://www.foia.gov/developer.html) has an [Excel spreadsheet](http://www.foia.gov/full-foia-contacts.xls) of contact info, but it is very incomplete.

This data is meant to be a starting point -- something that can be easily corrected, expanded, and repurposed. Perhaps someday it should be moved to its own repo, where it can become the canonical dataset for FOIA contact information in the US federal government.

Errors to report to agencies:

* NASA has a fax number of `(256) 544-007`