Library screen - Recyclerview repositioning issues [Sir Black Energy, Cat Knight]

[RobbWatershed]

Current behaviour
Variant 1
On some phones, the library activity will be killed while the user uses the image viewer (brutal memory optimization ?).

As a consequence, when going back to the library activity, the list may not remember its position (item 0 of current sorting is displayed on top of the screen).

Variant 2
When going back to the library screen from the image viewer, the main list sometimes "teleports" to position (number of books per page x2).

Expected behaviour
Even when killed under pressure, the library activity should remember its exact position of the list when going back from the page viewer

See https://stackoverflow.com/questions/52587745/how-to-save-and-restore-scrolling-position-of-the-recyclerview-in-a-fragment-whe

[RobbWatershed]

Part of the issue --> mikepenz/FastAdapter#861

[RobbWatershed]

Codename Liza