By Denny Dyroff, Staff Writer, The Times The singer who is headlining the show on October 16 at the Sellersville Theater (24 West Temple Avenue, Sellersville, 215-257-5808, www.st94.com) released his first single in 1952. Now, 64 years have gone by and he’s in no rush to make his final single. But, he’s always in a rush – he’s Bobby Rush. The veteran bluesman is now in his 80s and is showing...