Boston TV icon Rex Trailer died Wednesday night, his family announced on his website Thursday. Trailer, 84, was the host of the popular children’s television show “Boomtown,” on WBZ-TV from 1956 to 1974. The program often included children with disabilities in the studio audience. Trailer, who lived in Sudbury, was in Florida for Christmas visiting his sister when he came down with pneumonia and went into the hospital. His family issued this brief statement: Rex Trailer left this earth peacefully last night surrounded in love and song by his family. Rex had been in Florida for the holidays when he...