CPS Energy is putting several downtown properties, including its headquarters, up for sale and has chosen a real estate company to market them. CPS Energy's board voted Monday afternoon to classify several properties as surplus. The properties now listed as surplus are CPS Energy's current headquarters at 145 Navarro St., a building and parking garage at 146 Navarro St., its share of a parking lot on the 100 block of Navarro Street, the La Villita Assembly Hall, a property off Jones Avenue and…