Revert "WIP - handing accessory view to the popover"

This reverts commit 23be60364f2ddf672713549688e38e3492af1e20.
Revert "Decide on navigation toolbar visibility earlier in the process"

This reverts commit ba1f06c844cfceafe72e0a192cc6a43eab37d8a3.
Minor fixes for pop over display. Allow overloading of the popover background view class