(Reuters) - The atmosphere is "buzzing" at the sellout Irish Open at Royal Portrush and the tournament has the feel of a major championship, world number 11 Graeme McDowell said on Tuesday. The appearance of Northern Irish trio McDowell, Rory McIlroy and British Open winner Darren Clarke at this week's event, plus triple major champion Padraig Harrington of Ireland, has helped the European Tour ...