The world's oldest head of state - 92-year-old Paul Biya - has promised Cameroon's electorate "the best is still to come" as he seeks his eighth consecutive presidential term on Sunday. The nonagenarian has already been in power since 1982 - another seven-year mandate could see him rule for 50 years until he will be almost 100. He defied widespread calls to step down and has been criticised for only showing up for one rally, spending most of the campaign period on a 10-day private trip to