Fix WOFF file support.

This commit resolves:
- 'src' and 'local' attributes in 'font-face' CSS values
- invalid font weights and styles

Issues:
http://code.google.com/p/phantomjs/issues/detail?id=592
http://code.google.com/p/phantomjs/issues/detail?id=247
http://code.google.com/p/phantomjs/issues/detail?id=713