Export methods for subclass about <titleForCard>

- Export two methods, <titleForCard> and <backgroundImageForCard>.
- Modify returning type to NSMutableAttributedString for attributed
title.
Improve with attributed string in title of cards.

- Re-write <titleForCard> to display attributed string in title of
cards.
Reduce font size of title of cards.

- To fit attributed string.
Initial the re-write method <titleForCard>

- Not yet do any modification on it about attributed string on Set
cards.