(Reuters)  Filipinos have scoffed and slurped to show their backing for Davao City Mayor Rodrigo Duterte ahead of next week’s presidential elections. The maverick mayor of the southern city is leading the “Gulp Poll” conducted by convenience store chain 7-Eleven, which has asked customers at their 1,650 outlets across the country to pick soda cups with images of their favorite presidential candidate. The popularity of Duterte’s blue cup has mirrored two opinion polls last week […]