Update Unicode-Collate to CPAN version 1.04

  [DELTA]

1.04  Sat Dec  7 11:34:18 2013
    - XS: a workaround for perl 5.6.x to handle U+FFFF correctly.
      unpack_U() is implemented by using XS again as well as that in 1.02,
      but now that is used only in the versions before perl 5.8.0.