(Tallahassee, FL)  --  Florida State quarterback Jameis Winston is not being charged with sexual assault.  The State Attorney's Office said this afternoon the results of its investigation didn't turn up enough evidence to move forward with the case.   A 19-year-old woman told police Winston raped her last December.  A felony charge would have resulted in Winston's immediate suspension from the team.  Winston is considered the frontrunner for the Heisman Trophy, and FSU is number one in the BCS standings.