IGUALA Mexico (Reuters) - The body of a Roman Catholic priest from Uganda who went missing in southwestern Mexico has been found in a mass grave as authorities search for the remains of 43 missing trainee teachers feared massacred, the local diocese said on Friday.The remains of the priest, identified as John Ssenyondo, were dug up about a week ago and identified by the recovered skull as well as dental records. He had been missing since May, the state attorney general's office said."It was found in a mass grave with six other bodies," said a spokesperson for the diocese of...