Turkish President Recep Tayyip Erdogan conceded defeat on Sunday in the country's local elections, saying the vote was a "turning point" for his party after two decades in power.Partial results from across the nation of 85 million people showed major advances for the Republican People's Party (CHP) at the expense of Erdogan's Justice and Development Party (AKP).Istanbul's mayor, the opposition's Ekrem Imamoglu, claimed re-election with nearly all ballot boxes opened, telling a euphoric crowd of supporters: "Tomorrow is a new spring day for our country."