Nick Symmonds, the Run Gum CEO who defied USATF over its wear-Nike edict, turned 35 on Sunday and came out with a video Thursday. He says he’s unretiring. But Nick’s not making a comeback in the 800, where he won a world silver medal and competed in two Olympics. He says he can’t turn left anymore. So he’s challenging himself in a completely new event: the 100-meter dash. He has a 400 PR of 47.45 and figures he once was in 10.5 to 11 shape for the 1. He’s also using his YouTube channel to promote his brand and training…