Add an extractor for internetvideoarchive.com videos

It's used by videodetective.com

youtube_dl/extractor/__init__.py

@@ -62,6 +62,7 @@ from .ign import IGNIE, OneUPIE
 from .ina import InaIE
 from .infoq import InfoQIE
 from .instagram import InstagramIE
+from .internetvideoarchive import InternetVideoArchiveIE
 from .jeuxvideo import JeuxVideoIE
 from .jukebox import JukeboxIE
 from .justintv import JustinTVIE