Forget air miles and cash back. The latest credit card reward is more time swinging a sword and collecting treasure on your PC.Vidgame publisher Blizzard Entertainment has teamed with First National Bank of Omaha to make a “World of Warcraft” credit card. Available in 13 fantasy-themed designs, players earn a reward point for every dollar they spend. 1,500 points equals one month of free play, which costs $15 in real money. And luckily for “Warcraft” addicts, they can use the card to shop online without ever having to stop playing.