Nintendo has reported a third solid month for its 3DS, once again claiming the top spot as the best-selling game platform. Carried significantly by Animal Crossing: New Leaf — which sold 150,000 combined digital and packaged units in July, for a total of 660,000 units since its release in June — the platform saw a year-on-year sales increase of 45 percent for software and 14 percent for hardware in July. The publisher also announced that 3DS title Luigi's Mansion: Dark Moon, which launched in March, had surpassed 820,000 combined physical and digital units in July. Meanwhile, software sales for Wii U are chugging along, with New Super Mario Bros. U surpassing…