clarify copyright

Please see facetracknoir/develop:

336fc06ebe550d2c5fefae7dc1f967377eef998d

https://sourceforge.net/p/facetracknoir/codegit/ci/336fc06ebe550d2c5fefae7dc1f967377eef998d/tree/

% git clone http://git.code.sf.net/p/facetracknoir/codegit

Signed-off-by: Stanislaw Halik <sthalik@misaki.pl>