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-1370780175378](https://f.cloud.github.com/assets/789082/628833/98c64a84-d0fe-11e2-9458-dda03e7bf67b.png)