add replay audio button to action bar, and use drawables for inline buttons

The replay buttons look a bit pixelated to me on high resolution screens, so I wanted to increase the resolution of the file. I also added an icon to the replay audio button in the action.

There isn't a huge difference in the image quality, but I think you can notice the improvement in this before/after
![before_after](https://cloud.githubusercontent.com/assets/2818274/4703199/c55d6fbc-5868-11e4-9f4b-8dc70d6f0cef.png)