Fix for Freestyle face marks incorrectly reset when feature edges are split at 2D intersections.
Problem report by an anonymous forum user with a .blend file for reproducing the bug, thanks!

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57488 954f8c5b-7b00-dc11-b283-0030488c597c