The company is tossing an unpopular fee but prices are still going up.Shares of Unity Software (U 9.79%) were slightly down in early trading on Thursday. But just before noon ET, the stock suddenly popped due to a big announcement regarding its pricing structure. As of 2:30 p.m. ET, Unity stock was up about 12%.Unity waves the white flag on runtime feesMany of Unity's customers use its software to create mobile games and monetize them. And the company has long sold its software as a subscription, charging d ...