Display team badge on team page

On tag pages
![screen shot 2014-10-07 at 13 55 00](https://cloud.githubusercontent.com/assets/1492162/4542417/42f47346-4e21-11e4-993f-3b065e5af29b.png)
![screen shot 2014-10-07 at 13 54 10](https://cloud.githubusercontent.com/assets/1492162/4542415/42dad1a2-4e21-11e4-8671-b6b3022e591e.png)
![screen shot 2014-10-07 at 13 53 11](https://cloud.githubusercontent.com/assets/1492162/4542416/42e7d870-4e21-11e4-87cb-609b5fe241f5.png)

Because we compose the image url from the PA ID, in some cases (a few) the image might not be on the server and this avoids displaying the default browser "image not found" image. It's the same practice we apply to the match header http://www.theguardian.com/football/2014/oct/05/west-ham-qpr-premier-league-match-report