Momondo Group was sold to Priceline, owner of rival Kayak, in a $550 million deal. The two Momondo Group brands, Momondo and Cheapflights, will fall under the Kayak division. Another impressive European travel tech success story, made even more impressive by the fact that Momondo underwent major strategic transformations during its development (acquisition, merger and strategic shift by Cheapflights into meta-search). Growth investor Great Hill owned a majority stake of…