HAVANA, Aug 31 (Reuters) - Talks aimed at resuming direct postal service between the United States and Cuba, which has been suspended for decades, are set to be held in mid-September in another sign of thawing U.S.-Cuba relations, Western diplomats said. (snip) The United States has approached Cuba before about resuming direct postal services but Cuba has insisted in the past that, among other things, this must be accompanied by a resumption of regular scheduled commercial flights between the two nations just 90 miles (145 km) apart. Currently, only charter flights are permitted under U.S. regulations. Cuba is also said...