Colin Dyckman and his wife, Kendal Reynolds, arrived in Italy just in time for a heat wave.  “Like the natives, we just strolled from gelateria to gelateria,” he recalled.  Spooning the silky frozen confection was a sweet alternative to sipping alcoholic beverages—and the experience was just as relaxing, he maintained. “It allows people to chilly, literally,” Dyckman said of …