Make fnote data model require a working cursor and test undo-ability of move
Make set_key take a work cursor and use it; test ability to Undo renumber
Add go_to_line and get_line methods for use from Footnote panel.
remove debuggery
Set up signalling between data and view. Use the signal for both metadata and refresh.
Display key class names not just numbers
Fix sorting of orphan anchors.
Make SUSPICIOUS_NOTE_SIZE smaller, 15, and SUSPICIOUS_NOTE_DISTANCE larger, 50