fix #1381: show language's native names if possible in the installed language list

Short change. New utility function (`lang_best_name`) allows us to choose the best name to display for a language. Then use that function in the language list before we hand off to the template.


Picture time!
![translatedlangs](https://f.cloud.github.com/assets/191955/2055906/418d9a4a-8acd-11e3-9c1a-1620297fa3c5.png)