The 6 Points Music Festival kicked off yesterday, appropriately on the 6th of the month, with shows at three locations around the D.C. area: Staccato in Adams Morgan, Austin Grill in Silver Spring, and a three band line-up that DCist caught last night at Clarendon Grill in Arlington. Having never seen a show at this venue, I was pleasantly surprised by the atmosphere, but frustrated by a sound issue that persisted throughout the night, which…