-- @usage split(",%s*", "Anna, Bob, Charlie,Dolores")
-- @usage split(""," x y") gives {"x","y"}
-- @usage split("%s+"," x y") gives {"", "x","y"}
-- @usage split(",%s*", "Anna, Bob, Charlie,Dolores")
-- @usage split(""," x y") gives {"x","y"}
-- @usage split("%s+"," x y") gives {"", "x","y"}