Acclaimed Bulgarian directing duo Kristina Grozeva and Petar Valchanov (“The Father”) are in post-production on their fifth feature, “Black Money for White Nights,” an absurdist tale about a middle-aged couple who lose their life savings in a travel scam. The directors will be presenting the film during the Works in Progress program of the Thessaloniki Film Festival ’s industry arm, Agora, which takes place Nov. 2 – 6.  “Black Money for White Nights” is the story of Marina, a maternity nurse,