THINGS TO DO Lots To Do Outside, From Art By The Lake To R-boom Power Days By LIBBY CUDMORE • Special to www.AllOTSEGO.com The only thing better than art is Art By The Lake! The annual juried art exhibit celebrates the relationship between artists and landscape. Features artist demonstrations, food by Origins Cafe, music, more. 10 a.m.-5 p.m., Saturday, Aug. 17, back lawn, The Fenimore Art Museum, Cooperstown. (607) 547-1400. The annual Antique Power Days showcases tractors and farm vehicles…