[ndr] Add support for ndr.de (Closes #2325)

youtube_dl/extractor/__init__.py

@@ -142,6 +142,7 @@ from .myvideo import MyVideoIE
 from .naver import NaverIE
 from .nba import NBAIE
 from .nbc import NBCNewsIE
+from .ndr import NDRIE
 from .ndtv import NDTVIE
 from .newgrounds import NewgroundsIE
 from .nfb import NFBIE