Changed media buttons from white to dark when using a light theme.

I noticed that the media buttons are too light to see when using the light themes.  Here is an update if you choose to use it that changes the buttons to a transparent black. The images remain light when using the holo and dark themes with this change. 

Hope this helps. 

Aaron

![Screenshot_2013-01-08-15-59-22](https://f.cloud.github.com/assets/1691142/51618/967a918e-59d7-11e2-8d98-dc018e39d6e4.png)