One of my most anticipated sets at this year’s Umbrella Music Festival is Saturday night, when fantastic Boston pianist Pandelis Karayorgis returns to town to front his Chicago-based quintet at the Hideout on Saturday. That band includes bassist Nate McBride, a old partner from their Beantown days together, as well as reedists Dave Rempis and Keefe Jackson and drummer Frank Rosaly; it’s one in Karayorgis’s long line of collaborations involving Chicagoans. Last month another of those groups, the Whammies, released its first album, and it’s a doozy.