a/v setting tab redesign

and I renamed a lot of variables, I gave them meaningful names.

![before](https://cloud.githubusercontent.com/assets/3148759/4680955/17e4d06a-560f-11e4-9286-a83fbba8b1d1.png)

![after](https://cloud.githubusercontent.com/assets/2544251/4701939/5bd8366c-585e-11e4-8f82-bef2e18a50fd.png)