[douyutv] Add new extractor

youtube_dl/extractor/__init__.py

@@ -106,6 +106,7 @@ from .dctp import DctpTvIE
 from .deezer import DeezerPlaylistIE
 from .dfb import DFBIE
 from .dotsub import DotsubIE
+from .douyutv import DouyutvIE
 from .dreisat import DreiSatIE
 from .drbonanza import DRBonanzaIE
 from .drtuber import DrTuberIE