developer iarc rating pages (bug 931939)



Review here: https://github.com/ngokevin/zamboni/commit/4e638cdff0547f2dd39406c1bdaa0a877ae7ed65


Developer rating pages. @robhudson

- Ignore the first two commits, they're part of https://github.com/mozilla/zamboni/pull/1308
- Waffled under ```iarc```
- If no content rating, the page shows the edit view. If there is, it shows the summary view (table).
- Clicking on the ```Edit``` link in the summary table swaps out the section with the edit view via JS. Likewise, clicking back swaps back to summary table

**Screenshots:**
![screen shot 2013-10-28 at 9 11 13 pm](https://f.cloud.github.com/assets/674727/1425917/3a498536-4050-11e3-9f9b-868601e94166.png)

![screen shot 2013-10-28 at 9 11 18 pm](https://f.cloud.github.com/assets/674727/1425915/33c6f0fe-4050-11e3-9baa-7b90e00adae7.png)