The Algerian authorities said Friday that voters overwhelmingly approved a referendum that the president had promoted as a way for Algeria to move past the killing and violence of a civil war that spanned more than a decade. This nation's referendum on Thursday was an emotional moment for many Algerians, who had to decide whether to accept their president's request to forget the violence of a civil war that left more than 100,000 people dead and to offer amnesty to many of those responsible.