The Porch Southern Fare & Juke Joint, the new restaurant featuring Southern food that opened this summer at River’s Edge, continues its live music nights with a free performance by Stan Martin. Martin has been a fixture on the small but authentic Boston country music scene for over a decade. His tasty blend of southern rock and Bakersfield twang is kind of what you’d get if you blended the early Eagles with Telecaster ace Danny Gatton. It’s got a California flair and an East Coast swagger and it’s good…darn good.