Fixed menu XML, added scroll to dismiss listeners for AbsListView and RecyclerView

Following changes have been made:
* Fixed an issue with the sample menu XML file to work with AppCompat
* Added `attachAbsListView(AbsListView absListView)` and `attachRecyclerView(RecyclerView recyclerView)` methods to allow for on-scroll dismissibility for snack bars, akin to that in the Inbox app from Google.
* Added new art screenshots and updated README.md to reflect the changes