twn_util: final cleaning up, introducton of powerful file_read()

apps/demos/platformer/game.c

@@ -29,10 +29,6 @@ void game_tick(void) {
         ctx.debug = !ctx.debug;
     }
 
-    if (input_action_just_pressed("debug_dump_atlases")) {
-        textures_dump_atlases();
-    }
-
     state->scene->tick(state);
 
     /* there's a scene switch pending, we can do it now that the tick is done */