Trump claimed the election was rigged in 2012 after Romney lost. I see him and his supporters doing this but calming down after a few weeks. I don't see them being violent. If he was wins it will be Brexit but 1000% maximum. He will be a lame duck president congress will completely shut him out.
Of course I really want Trump to win the presidency. But I'd be fine with a Hillary victory too, as long as Hillary doesn't go far to the left and stay where she is perfectly in the center.