[comedycentral] Add new extractor for full-episodes

CC seems to have added yet another indirection for full episodes - the mgid is now only in a linked feed.
This may be a little brittle, but it's better than failing outright.
Plus, the current The Daily Show episode now works :)

youtube_dl/extractor/extractors.py

@@ -180,6 +180,7 @@ from .cnn import (
 from .coub import CoubIE
 from .collegerama import CollegeRamaIE
 from .comedycentral import (
+    ComedyCentralFullEpisodesIE,
     ComedyCentralIE,
     ComedyCentralShortnameIE,
     ComedyCentralTVIE,