make matrix headers optional
make matrix headers optional

berkeleybop/bbop-js,berkeleybop/bbop-js,berkeleybop/bbop-js,berkeleybop/bbop-js,mugitty/bbop-js,mugitty/bbop-js,mugitty/bbop-js,berkeleybop/bbop-js,mugitty/bbop-js,mugitty/bbop-js