Enhanced Unsharp Mask in PhotoFlow - please test!

[heckflosse (Ingo Weyrich)]

@Carmelo_DrRaw

@heckflosse you did quite some work on preserving smooth areas from sharpening. Would be interesting to compare the two approaches… do you have some test image that we could use for the comparison?

The one from this play raw? Sun and Thunder in Geneva - #20 by kakashy