This module provides a Unix-like command `crosstable'. 
It outputs the 2-way contingency table from a 2-columned TSV file,
as well as many related minor functions. 

=head1 DESCRIPTION



 Copyright (c) 2021 Toshiyuki SHIMONO. All rights reserved.
 This program is free software; you can redistribute it and/or
 modify it under the same terms as Perl itself.