Add an extractor for videofy.me (closes #1171)

Also modify find_xpath_attr to accept values with spaces like for id="HQ on"

youtube_dl/extractor/__init__.py

@@ -73,6 +73,7 @@ from .ustream import UstreamIE
 from .vbox7 import Vbox7IE
 from .veoh import VeohIE
 from .vevo import VevoIE
+from .videofyme import VideofyMeIE
 from .vimeo import VimeoIE, VimeoChannelIE
 from .vine import VineIE
 from .c56 import C56IE