Fixed issues, now sliders can be adjusted with mouse scroll wheel

[Equbuxu]

All good, but I would increase scroll sensitivity. It's too slow in my opinion. Or add it as Dependency Property.

Actually, this is by design since the whole point of the feature is to allow more precise control (it's hard to finely adjust the slider otherwise). In fact, I was contemplating making it 1 unit per scroll since that's how it usually works. I can add it as a dependency property but it should stay low in PixiEditor

[flabbet]

For PixiEditor it's fine I guess, but I would add it as a dependency property for anyone who would like to use it in their project.

[Equbuxu]

Added dependency properties, they are not completely polished in that you have to specify values from 0 to 1 even though values in textboxes go from 0 to 255. I'm going to rework this system anyway in 3.0.0, so I figured it will be fine as-is for now.