When New York-born, London-settled vocalist Joy Marshall died in November 1968, her obituaries unsurprisingly concentrated on the salacious aspects of her death, which in retrospect, seemed all but inevitable considering the fast lane in which she lived her life.  But today, with decades having passed, one can more fairly evaluate Marshall’s career solely on her art.  Based on the upcoming release due May 18 from Cherry Red’s Turtle imprint of When Sunny Gets Blue: Spring ’68 Sessions from The Gordon Beck Quartet featuring Marshall, she was a vocalist with which to be…