BOX SET Dave Matthews Band Europe 2009 [Bama Rags/RCA] “You are my obsession!” Dave Matthews sings during “Seven”—no doubt taking the worshipful words right out of his one-track-minded audience’s mouths. It will indeed take a certain kind of obsessive to spring for Europe 2009, a not-inexpensive four-disc set that uses one DVD to present a nearly three-hour London show from last summer, then spreads an even longer Italian gig across three...