"He was the nicest guy. He was so talented," Treat Williams' agent, Barry McPherson, tells PEOPLE Treat Williams, the star of Everwood and Hair, has died after being involved in a motorcycle accident. He was 71. The actor's death was confirmed to PEOPLE on Monday evening by his agent of 15 years, Barry McPherson. "He was killed this afternoon. He was making a left or a right [and] a car cut him off," McPherson says. "I'm just devastated. He was the nicest guy. He was so talented." "He was an actor's actor. Filmmakers loved him. He's been the heart of...