Just a wisp of time elapsed, and the almighty sand-gnat is back with a vengeance. Like a swallow returning to Capistrano or a martin to a gourd, the little varmints are back just in time for the Blessing of the Fleet. They just refuse to give up.Last year, my Yankee cousin came to the waterfront for the concert and fireworks, but he forgot his Avon Skin So Soft.