Paginator that uses all available screen/window width

yet another set of bugfixes

The key API change I'd underestimated: opening a file used to return nil on failure, and now returns false.

Created by  Kartik K. Agaram  on August 31, 2023
MEP2P6K7VTQ7B5JT4ZQFOWJAEWY7VTBDDQRB47JMX5PXBWZZCOWAC
Change contents