fragment
       This, for now experimental, function tries to implement RFC7111 (URI
       Fragment Identifiers for the text/csv Media Type) 1)

        1) http://tools.ietf.org/html/rfc7111

        my $AoA = $csv->fragment ($io, $spec);

       In specifications, "*" is used to specify the last item, a dash ("-")
       to indicate a range. All indices are 1-based: the first row or column
       has index 1. Selections on row and column can be combined with the
       semi-colon (";").

       row
          row=4
          row=5-7
          row=6-*
          row=1-2;4;6-*

       col
          col=2
          col=1-3
          col=4-*
          col=1-2;4;7-*

       cell
         In cell-based selection, the comma (",") is used to pair row and
         column

          cell=4,1

         The range operator using cells can be used to define top-left and
         bottom-right cell location

          cell=3,1-4,6

       RFC7111 does not allow any combination of the three selection methods.
       Passing an invalid fragment specification will croak and set error
       2014.