The singer, songwriter and guitarist Dave Mason, who has died aged 79, was the superstar who never was. He first found fame as a founder member of Traffic, and wrote some of the most popular songs from their early repertoire, but could never quite see eye-to-eye with the band’s precocious genius Steve Winwood. Mason’s self-evident talents, which included copious skills on acoustic and electric guitars and a grainy, soulful singing voice, then allowed him to form creative relationships with some of the biggest names of late-1960s and 70s rock, including Jimi Hendrix, Eric Clapton, the Rolling Stones, Delaney & Bonnie, George Harrison , Cass Elliot and Crosby Stills and Nash – though never on a long-lasting basis. In 1975 he featured on the US chart-topping single Listen to What the Man Said by Paul McCartney’s Wings, and in the mid-90s he was temporarily a member of Fleetwood Mac, featuring on their album Time (1995), for which he co-wrote a couple of tracks.…