Lighter blue colour for filtered decks in deck list.

Filtered decks are blue on the desktop client. AnkiDroid already applies a colour, but it's almost impossible to discern from the normal deck colour. This makes it more blue.
![screenshot-1370779000130](https://f.cloud.github.com/assets/789082/628822/8cac4a48-d0fc-11e2-8772-fe00df295da2.png)