Jet-set conductor Donald Runnicles is all over the map, literally. In Berlin, he’s music director of the German Opera. In Wyoming, he heads the Grand Teton Music Festival. And he often visits Georgia as principal guest conductor of the Atlanta Symphony Orchestra. It all began in Scotland, where Runnicles grew up the son of a church choirmaster and an amateur pianist. In May, between weekends of Debussy and Beethoven with the ASO, he sat down with GPB’s Sarah Zaslaw. She asked about his earliest musical experience.