LIBREVILLE, Gabon (AP) — Opposition candidate Jean Ping vowed to not back down from his pursuit of the presidency hours after the constitutional court upheld the victory of incumbent President Ali Bongo Ondimba, whose family has been in power for nearly half a century. Ping and his supporters have accused the ruling party of vote-rigging, and the opposition leader reiterated his call Saturday for people to object. [...] the opposition has said that as many as 100 people have been killed while some 1,200 have been detained by authorities as part of a government crackdown on dissent.