Changelog:
- choose only exactly matching strings in chooser
- speed up getMaxWidth() for wide columns
- Default disp_histogram to U+25A0 BLACK SQUARE
- do not truncate wide columns with fixed-width saver
- add missing import copy
- allow filling with values that are logically false
- add new rows to sheet on paste
- show correct progress for compressed files
- undo is Sheet-specific on copied sheets
- undoing zd now removes modification mark
- update for Python 3.12
- many bugfixes