Walking into Jammin’ Java Friday night, here’s what I knew about Philly rockers Marah: 1) High Fidelity and About a Boy author Nick Hornby, a man who has documented his musical preferences at least enough for me to know I largely share them, loves on this band so much he devoted one of his book columns in Believer magazine a couple of years ago to their largely unsung magnificence. 1a) Stephen King –Josh Ritter…