Like so many of the people who became part of the bedrock of San Francisco’s colorful music scene in the mid- to late ’60s, Janis Joplin got her start in folk music. A couple of years after graduating from high school in the small town of Port Arthur, Texas, where she was an outsider who hung with Bohemian types and was castigated for her support of civil rights, she moved to the University of Texas in Austin and joined a folk/old-time/blues group called the Waller Creek Boys,…