NEW YORK (Reuters) – DirecTV, the No. 1 U.S. satellite TV operator, said on Sunday it has agreed to sell itself to ATT for $48.5 billion in the second mega-deal to shake up the U.S. television landscape this year. Here’s a look at both companies, with a focus on which of their services may be combined in the deal. ATT * Market capitalization of $189 billion * 5.7 million U-Verse television customers * 4. …