By Denny Dyroff, Entertainment Editor, The Times Renaissance If something lasts for 50 years, it must have something going for it. If a music act lasts for 50 years, it definitely has something going for it – something that translates into guaranteed staying power. Two acts that have lasted a half-century are the Nitty Gritty Dirt Band, which was formed in 1966, and Renaissance, which will celebrate...