Add .sortoptions styling

Hi,

Thanks for this great admin skin! I made a small improvement by adding styling for the .sortoptions elements:

![sortoptions](https://f.cloud.github.com/assets/1597703/1590734/7569df56-5295-11e3-8b11-0bd826b397bf.png)

Tested in IE8, IE9, Latest FF and Chrome.

Regards,

Erik-Jan