Commentary changes from review
Modify to use paths setting instead of obsolete dictionaries setting
Commentary and error message edits during review.
Get test page model from default book
Back out ill-advised change made in haste
Change to use proper mainwindow display instead of faking it
Implement equal-width for zoom buttons, plus misc commentary and format edits
Adjust a margin factor and fix a comment typo
Minor commentary and other review tweaks
Bring tests current with actual code
Improve commentary on PANEL_DICT
Make tests match updated code, and use normal mainwindow
Use real mainwindow and book, fix error in test expectations
Update commentary. re-code iterators to use isValid and more complete error checks.
Correct mod status after loading an existing book:
Bring tests up to date
Change method of highlighting current line
Numerous changes to logic of show_ and center_ methods and general cleanup. Bad, I know.
Bring up to date and correct for changed log messages