BERLIN, May 26 (Reuters) - German police said on Friday they had launched an investigation into Pink Floyd co-founder Roger Waters after he wore a Nazi-style uniform on stage at Berlin's Mercedes-Benz Arena. The British 79-year-old was not immediately available for comment, but social media users came to his defence saying the performance was a recreation of satirical scenes from the film of the band's hit album "The Wall", a critique of fascism. Images from a concert on May 17 showed the famed singer and bass player in a long back trench coat with bright read arm bands, aiming an...