Allow downloading and deleting of dubbed videos through the topic tree

Fixes #858, #1374, and issues we haven't even dreamed of... ;)

I'm just going to brag, with some screen shots, as this is the first time we can see how dubbed videos fit into the topic tree.

![screen shot 2014-01-31 at 6 41 02 am](https://f.cloud.github.com/assets/4072455/2051271/23f5afaa-8a86-11e3-92a4-51dbe8f62f6e.png)
![screen shot 2014-01-31 at 6 38 09 am](https://f.cloud.github.com/assets/4072455/2051272/26d36e38-8a86-11e3-9c44-71539d97f5e1.png)
![screen shot 2014-01-31 at 6 40 51 am](https://f.cloud.github.com/assets/4072455/2051274/28db987c-8a86-11e3-84eb-493932070c64.png)