Comment 4 for bug 425929

As of this writing, revision 20 of gwui.py line 236 tries to convert a float that appears as string to an int. The value is retrieved from global application font preference. If you supposed have 8.5899, the conversion fails, but if you have an int it works ok.

So prior to casting to an int, if the value is first converted to a float, it does the trick of flooring the float value to an integer and the lower bound value is used in setting gwibber's application font size.