Copyright 2015, 2016, 2017 Kevin Ryde

This file is part of Graph-Graph6.

Graph-Graph6 is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.

Graph-Graph6 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with Graph-Graph6.  If not, see <http://www.gnu.org/licenses/>.



Version 7, May 2017
    - digraph6 everywhere
    - Graph::Reader::Graph6 of sparse6 create countedged if necessary
    - Graph::Graph6 constants HEADER_GRAPH6, HEADER_SPARSE6, HEADER_DIGRAPH6

Version 6, August 2016
    - Graph::Writer::Sparse6, Graph::Easy::As_graph6,
      Graph::Easy::As_sparse6 document header option

Version 5, October 2015
    - new GraphViz2::Parse::Graph6

Version 4, August 2015
    - Graph::Graph6 read_graph() propagate taint of input

Version 3, May 2015
    - fixes for writing named file

Version 2, May 2015
    - Graph::Graph6 read_graph() delete previous edge_aref contents
    - Graph::Easy as_graph6() fix for undirected graphs

Version 1, May 2015
    - the first version