Minor Stability Improvements

Hi folks,

first of all, thank you for this great widget - your approach of retrieving the wrapped views from the xml layout inspired me for another utility of mine.

Unfortunately on a couple of devices (e.g. Galaxy Note) our team experienced a RuntimeException in the Fonts utility which should be fixed with my commit. I hope this is a valuable contribution to your repository. In case a font fails to load, the app will not crash anymore but rather set no font at all.

Best regards,
Michael