Made favourite stars more visible.

I couldn't really see the previous favourite stars on some shows with dark banners so this is a suggestion.
I've only tried this on my Galaxy SII which uses drawable-hdpi, so I don't know if the m- and xhdpis look good.

Screens:
<img src="https://cloud.githubusercontent.com/assets/3090888/5475516/e796394a-8619-11e4-8775-8a08e505cbdc.png" width="50%" />