By Bill Knight Five years ago this week, cartoonist June Brigman took over the iconic newspaper comic strip “Mary Worth,” continuing a popular feature whose roots some say are tied to a Depression-era strip with a lead character of the same name but much different circumstances. Brigman is a veteran illustrator, working on comic books including “Supergirl” (DC) and “Power Pack” (Marvel), plus “Star Wars” titles and the “Brenda Starr” strip. “Mary Worth” syndicator King Features disputes a connection to “Apple Mary,” an oft-forgotten strip by Martha Orr about a pluc...