ui tweaks for more visibility

Not sure if all platforms suffer from this, but here's what I see on OSX:

![orig](https://cloud.githubusercontent.com/assets/368894/2937890/111efd7c-d8de-11e3-83fb-4b3934d6f624.png)

There are several problems:

1. The episode list is very narrow and hard to see enough detail
1. The episode and show lists are too short when you have many, but they do not expand to fill vertical space, as shown in the next screenshot
1. When the vertical size is stretched, the UI on the left becomes quite spaced out

![nogrow](https://cloud.githubusercontent.com/assets/368894/2937904/11d949ce-d8df-11e3-9d1a-c944a7855a89.png)

This pull request aims to fix both problems. The changes made:

1. Show list is 50px wider
1. Episode list is 150px wider
1. Download button placed under quality selector to accommodate the other wider elements
1. The left hand UI elements no longer stretch vertically

![new](https://cloud.githubusercontent.com/assets/368894/2937891/15e4ca76-d8de-11e3-80a1-8a92d5485a5e.png)