Circular cropping on android.

[Pyroboomka]

Hello!
Thank you for the great work in updating the library.

Is it possible to have circular cropping in android part of the library?
Made it work on iOS after digging in source files (circleCropRadius/showCropCircle combo), but android is kinda tough.

It seems that library that RXGallery is using for cropping (https://github.com/Yalantis/uCrop) can do circular shapes based on github description, but finding the correct flag to toggle is hard for me since I have 0 android development experience.

cropOvalDimmedLayer() method on rxGallery instance looked promising, but gave no results.
Maybe you can save me and others some time digging through source codes of both projects.

Thank you!