Add proper 3-letter team codes to football stats

Updates to latest PA Client, which includes the curated 3-letter team codes.

Before:
![3-letter-team-code-before](https://cloud.githubusercontent.com/assets/29761/2654954/01e7d34c-bfde-11e3-8c2f-10d37805d703.png)

After:
![3-letter-team-code-after](https://cloud.githubusercontent.com/assets/29761/2654956/0f0f860a-bfde-11e3-8ad0-a3985f2fe902.png)

See also https://github.com/guardian/pa-football-client/pull/29