Angry Birds 2, the sequel to the mobile hit Angry Birds, has been announced by developer Rovio Entertainment.After 15 games and around 3 billion downloads for the series, Angry Birds 2 will arrive on July 30, and will be the first full sequel to the 2009 hit. Rovio is promising more information later in July.Although this is the first full sequel, the original game spawned numerous spin-offs and licensed adaptations, such as Bad Piggies and Angry Birds Star Wars.