From: Jakob Haufe <sur5r@sur5r.net>
Date: Thu, 29 Mar 2012 22:20:26 +0200
Subject: Ignore unused screenshot
+Bug: https://sourceforge.net/tracker/?func=detail&aid=3515881&group_id=46122&atid=445116
Ignore figures/main-window-empty.png as it's no longer used by the docs
and generates a self-referencing symlink.