Written by DCist Contributor Matthew Siblo In a year when the District’s summertime rituals were routinely threatened, the mere presence, however abbreviated, of the Fort Reno summer concert series was comfort in and of itself. As the series’ truncated six week calendar came to an all too abrupt finish on Thursday, it did so on an appropriately gorgeous evening with the eclectic pairing of The Grendel Babies, Casper Bangs, and Title Tracks. The Grendel Babies…