Improve action bar spinner style in card browser

Title and subtitle of the deck picker in the card browser now look exactly like the native ones in the deck picker. In landscape mode there is no cut-off subtitle anymore except if orientation is changed without reloading the activity (not too bad, I think, we should aim to remove `orientation` from `android:configChanges` in the future, but this will be a lot of work). Also I found a few magic variables to get rid of the custom `dimens.xml` (not sure why Eclipse doesn't expose them).
Apparently this is an appcompat thing.