Adds UA blacklist to @font-face test as a stopgap.
This addresses the issue of false positives on WebOS, Android 2.0/2.1,
and Windows Phone 7-7.8 while we consider a more robust feature test.
Ref. #1120.
Merge pull request #1147 from Wilto/master

Adds UA blacklist to @font-face test as a stopgap for false positives