- Use same names for options;
- Have them both movable
- Add option to keep widget shown on Apply (and use that
when appropriate: when the value may have an immediate
visual effect, so one can tweak it without having to
go thru menus to re-open it again).
Also adds options to remove statistics for books
with low reading duration (to clean up stats for
books just quickly browsed and not yet read).
Also adds TextWidget:getFontSizeToFitHeight()
even if we ended up not using it.
