#17 State License in *.c and *h files

[Jari Aalto]

The *.c and *.h files contain paragraph:

* This program is free software. It may be distributed under the terms
* in the file LICENSE, found in the top level of the distribution.

Please write the minimum license text as suggested by FSF. See

How to Apply These Terms to Your New Programs
http://www.gnu.org/copyleft/gpl.html