Results 2 issues of Daniel Luberda

- [ ] Bindable transformations properties - https://github.com/luberda-molinet/FFImageLoading/issues/499 - [x] XAML Previewer support - https://github.com/luberda-molinet/FFImageLoading/issues/418 - [ ] Add CachedButton implementation - https://github.com/luberda-molinet/FFImageLoading/issues/850

help wanted
Xamarin.Forms
up-for-grabs

Should be tested if it's worth to merge it.