make face culling optional

src/twn_loop.c

@@ -596,6 +596,13 @@ static bool initialize(void) {
             }
         }
         SDL_free(datum_font_filtering.u.s);
+
+        toml_datum_t datum_cull_faces = toml_bool_in(engine, "cull_faces");
+        if (!datum_cull_faces.ok) {
+            ctx.cull_faces = true;
+        } else {
+            ctx.cull_faces = datum_cull_faces.u.b;
+        }
     }
 
     /* these are dynamic arrays and will be allocated lazily by stb_ds */