EXCLUSIVE: While Mark Gordon-produced series are popular the world over, Darkness Falls marks the first time the prolific Mark Gordon Company is reaching into the international co-production space. MGC and Germany's ProSiebenSat.1 TV Deutschland are in the final stages of negotiations for the development of the procedural that’s based on an original script by Erica Messer (Criminal Minds, Criminal Minds: Beyond Borders, The O.C.) and Janine Sherman Barrios (Criminal…