PAP SAINE and EDWARD McALLISTER AT a pre-election rally last month, supporters of Gambia's main opposition coalition cheered the opening of the star attraction - a speech by former President Yahya Jammeh delivered over a crackly phone line from exile 2,000 miles away. "(President) Adama Barrow destroyed everything good I left for Gambians to benefit from - the hospitals, agriculture and education," Jammeh said to enthusiastic applause. "We should all unite and vote him out." Gambians go to the polls on Saturday and for the first time in 27 years Jammeh, who took power in a 1994 coup, will not…