Automation for testing items per page as per view settings

Test items per page for grid,tile and list view
Some comments about instantiating Visual:
- Shouldn't the kwargs be ints? If they MUST be strings for fill to work, I'd rather Visual did the work to make sure of that than make it the caller's problem.
- I think the extra `None` kwargs are distracting noise, and should probably go away.
- What does `ns` stand for? Seems like it should be `visual_setting`.
- settings is not so long a word that it needed to be abbreviated to `st`.

example: `ns = st.Visual