Arg [1]    : Species name to retrieve aliases for
               (may be an alias as well).
  Example    : Bio::EnsEMBL::Registry->get_all_aliases('Homo sapiens');
  Description: Returns all known aliases for a given species (but not the
               species name/alias that was given).
  Returntype : ArrayRef of all known aliases
  Exceptions : none
  Status     : Development