Create UI tests

[DanielNovak]

Try to research if UI testing of the library would be feasible. Tests would verify if the model is correctly retained and then removed in cases such as:

1. Activity created and activity removed (model is removed)
2. Activity rotated (model retained).
3. Fragment created and then removed from backstack (model removed)
4. Fragment created and then replaced by other fragment and not added to backstack (model removed)
5. Fragment created and replaced with other fragment and added to backstack (model retained)
6. Fragment rotated (model retained)
7. Fragment rotated in backstack (model retained).

Possibly other cases...