Changes for PDL::IO::CSV

0.006   2014/12/15
        - require PDL 2.006 as we need unpdl()
        - doc update: reading/writing from/to scalar variables
        - enhanced header param by rcsv* functions

0.005   2014/11/26
        - perl 5.8.9 compatibility

0.004   2014/11/26
        - doc improvements
        - replace die() with croak()
        - better warnings for perls without 64bitint

0.003   2014/11/25
        - first public release