By Stephen Nellis OAKLAND, Calif. (Reuters) - The chief executive of "Fortnite" creator Epic Games testified on Monday that he knew he was breaking Apple Inc's App Store rules by putting Epic's own in-app payment system into the game last year but wanted to highlight Apple's sway over the world's iPhone users, which now total 1 billion. "I wanted the world to see that Apple exercises total control over all software on iOS, and it can use that control to deny users' access to apps," Tim Sweeney said from behind layers of plexiglass in a federal courthouse in Oakland, California, on the first day of an antitrust trial against Apple.