Copyright for sgb source package in Xenial

This version of the package was debianized by
Julian Gilbey  on Tue, 7 Nov 1998 17:11:54 +0000.

It was downloaded from ftp://ftp.cs.stanford.edu/pub/sgb/

This is in non-free as there are restrictions on distributing changed
versions.

Copyright:

The Stanford GraphBase is copyright 1993 by Stanford University

This file may be freely copied and distributed, provided that no
changes whatsoever are made. All users are asked to help keep the
Stanford GraphBase files consistent and ``uncorrupted,'' identical
everywhere in the world. Changes are permissible only if the modified
file is given a new name, different from the names of existing files
in the Stanford GraphBase, and only if the modified file is clearly
identified as not being part of that GraphBase.  (The CWEB system has
a ``change file'' facility by which users can easily make minor
alterations without modifying the master source files in any
way. Everybody is supposed to use change files instead of changing the
files.)  The author has tried his best to produce correct and useful
programs, in order to help promote computer science research, but no
warranty of any kind should be assumed.