added an IE for Ehow videos

youtube_dl/extractor/__init__.py

@@ -13,6 +13,7 @@ from .dailymotion import DailymotionIE
 from .depositfiles import DepositFilesIE
 from .dotsub import DotsubIE
 from .dreisat import DreiSatIE
+from .ehow import EhowIE
 from .eighttracks import EightTracksIE
 from .escapist import EscapistIE
 from .facebook import FacebookIE