NEW YORK (Reuters) – Blending photo montages with at times a thick accent and a singing voice still soaring at the age of 70, Barbra Streisand performed on Thursday in her first big concert where it all began – her birthplace of Brooklyn, New York. In the second show of her "Back to Brooklyn" tour, Streisand performed for nearly three hours at a new 19,000-seat arena, kicking off the concert with the words "I've come home at last!" from the show tune "As If We Never Said Goodbye" from "Sunset Boulevard". …