By Jeremy Gaunt LONDON (Reuters) - Nearly four decades after his death, British singer-songwriter Nick Drake has never been as popular. Tribute singers, car and cough syrup advertisements, radio and film documentaries, and word of mouth have combined over time to turn Drake from unheralded 1970s musician into modern-day music lore. Now a new CD of Drake's songs covered by other artists and a remastered boxed vinyl of one of his few albums are set to add to the phenomenon and put his haunting, poetic music into the spotlight. ...