- Avoid large stack use here and there.
- Test suite improvements.
- Improve sylk writer. Don't ask.
- Teach ssdiff about column/row sizes.
- Teach ssdiff about defined names.
- Fix a few ssdiff crashes.
- Fix crash on text import.
Depends on D1811
Signed-off-by: Pierre-Yves <pyu@riseup.net>