Tommy Emmanuel, who appears at the Byham Theatre Sunday at 7:30 is part of a long tradition of fingerstyle guitarists. The Australian-born musician is renowned for a level of virtuosity and versatility not unlike that of his first guitar hero, Chet Atkins (1924-2001). The guitarist-producer, known primarily as a country player, was known for his diverse repertoire, and later gave himself the tongue-in-cheek title "C. G. P." or "Certified Guitar Player." Emmanuel is one of the elite quintet of friends on whom Chet bestowed that title. The others are singer-guitarist Steve Wariner, John Knowles, the late country star Jerry Reed and Paul Yandell, Chet's guitar accompanist on his stage shows.