Sort test image frames to preserve order of frames

evaluator/airborne_detection.py

@@ -85,7 +85,7 @@ class AirbornePredictor:
     def get_all_frame_images(self, flight_id):
         frames = []
         flight_folder = join(self.test_data_path, flight_id)
-        for frame in listdir(flight_folder):
+        for frame in sorted(listdir(flight_folder)):
             if isfile(join(flight_folder, frame)):
                 frames.append(frame)
         return frames