By Madeline Coleman Speedway Motorsports announced that its founder died of ’natural causes’ on Wednesday. One of NASCAR’s visionaries, Hall of Famer Bruton Smith, died Wednesday of “natural causes,” Speedway Motorsports announced. He was 95 years old. Smith was the founder and executive chairman of Sonic Automotive, Speedway Motorsports and Speedway Children’s Charities. While at the helm of the company, Speedway Motorsports became the first motorsports company traded on the New York Stock Exchange back in 1995. The company flourished, its holdings expanding to 11 facilities that host 13 NASC…