By Pedro Fonseca and Andrew Downie RIO DE JANEIRO, Aug 4 (Reuters) - Brazil's economy is heading for recession, the president is threatened with impeachment and a huge corruption scandal has engulfed the nation but Rio is riding a wave of confidence in its preparations to host the Olympics next year. The Games start on Aug 5, 2016 and most of the work will be completed on time, Pedro Paulo, the man coordinating the city's Olympic projects, told Reuters. "Nothing is behind schedule when it comes to the Rio de Janeiro Olympics," Paulo said. More...