Set selected item text colour to dark grey

Firstly, great work with the skin so far!

A small annoyance for me is the white text on a selected item, it's a little difficult to see.  Changing it to a dark colour is a lot more readable.

![Settings](https://cloud.githubusercontent.com/assets/4025899/4263785/24a94b7e-3c00-11e4-8035-93698f306527.png)
![Library](https://cloud.githubusercontent.com/assets/4025899/4263786/24b3e4b2-3c00-11e4-8a8d-3585f8ae54d8.png)
![Players](https://cloud.githubusercontent.com/assets/4025899/4263787/24b44b14-3c00-11e4-9916-c31f3e36702e.png)

This covers most cases, except text in the main menu and top drop-downs.