Support for DiffUtil / Granular Update Notifications

[jmar777]

Thanks for making this library available to the public - we've been using it for awhile now, and love it!

I went to refactor our backing RecyclerView.Adapter implementation today, with the aim of using DiffUtil to prevent some unnecessary recycles from happening.

Unfortunately, this introduced some rather unexpected behavior. While this view is loading, the cards switch view types to represent loading/loaded states, and additional cards can be introduced at various locations within the dataset. The experience we observed was that the currently viewed position seemed to jump around during this loading process, and we'd typically end up viewing the last card by the time everything settled.

Seeing as we don't have this problem when doing a straight notifyDataSetChanged(), I'm assuming this is the result of some of the more granular notification methods not being supported? Is this the case, and if so, are there any plans to support them?

Thanks again!