By Ed Osmond GULLANE, Scotland, July 20 (Reuters) - Rory McIlroy will try to play his way out of a dramatic form slump with a heavy schedule of tournaments in the United States including his PGA Championship title defence in New York next month. The world number two sloped out of the British Open on Friday, looking a dejected figure after dismal rounds of 79 and 75 meant he missed the cut in the third major of the season for the first time. The 24-year-old McIlroy complained of feeling "brain-dead" on the Muirfield links but he did at least try to explain the causes of his problems. ... More...