Add support for tvOS

[skrew]

No description provided.

[kishikawakatsumi]

@skrew Have you tested this change?

[skrew]

Yes, but TBH, i don't use it for the moment because of bugs in UICollectionView on tvOS 13.
Your lib have the same problems when builded for tvOS 13 (but it's not your fault, it's Apple)
See stackoverflow if you need more infos about this bug (there are a problem with the focus engine too)

BTW, the lib works on tvOS, i'd used it in my tvOS app

[kishikawakatsumi]

@skrew Great to hear that! Thank you.