ID3v2 padding won't increase beyond 1% of the file size.

Essentially the same as I suggested at #447.

I'm not sure why is this checking against the old padding from `d->paddingSize`.

And on the other hand, I can think of a case where the new calculated padding more than 1% of the file, but that is less than `DefaultPaddingSize`. So we would be rewriting the file even when not necessary.