get_root_terms.pl - Find all the root terms in a given ontology.
This script retrieves all the names of the root terms (and their IDs) in a given OBO-formatted ontology.
Erick Antezana, <erick.antezana -@- gmail.com>
Copyright (c) 2006-2012 by Erick Antezana
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.7 or, at your option, any later version of Perl 5 you may have available.