Show the A to Z list if only the "other" group is present.

https://www.pivotaltracker.com/story/show/82282148

If the topic curation has resulted in only the "other" group being published with any useable content, show in A to Z order instead, with the A to Z heading.

Before:
![screenshot 2014-11-17 14 05 42](https://cloud.githubusercontent.com/assets/109225/5070833/d9c1040e-6e62-11e4-8d91-fba96d68c3c8.png)

After:
![screenshot 2014-11-17 14 05 27](https://cloud.githubusercontent.com/assets/109225/5070837/df315f10-6e62-11e4-9ed0-44c4e9a3929e.png)