NEW YORK (AP) CBS chose the middle of the summer for Norah O'Donnell to debut as "CBS Evening News" anchor, so probably should not be surprised that not too many people noticed. The Nielsen company says that 5. 24 million people watched her newscast each day on average last week. That's essentially unchanged from the week before, when CBS was also a distant third in the ratings behind ABC's "World News Tonight" and NBC's "Nightly News. "There are different ways to look at the numbers. CBS up...