Layout of 1.3 scores
We need to decide how to handle 1.3 scores loaded into 2.0. So much has changed regarding layout that there is little chance 1.3 scores will look exactly the same when loaded into 2.0. In particular, there may be different number of measure per system for the same layout / stretch / style settings (most likely 2.0 will fit fewer measure on some systems), and also manual positioning of notes/accidentals/ties will likely not be correct given new improved default positions.
My initial proposal is that we do the following:
1) Automatically reduce stretch and/or minNoteDistance for 1.3 scores from what was specified, by maybe 5-10%, in hopes of fitting the same number of measures per system as before. If a score had explicit breaks, this should work well. If it didn't, then we might fit "too many" measures per system. But maybe that's OK. We could also consider only doing the automatic adjustment for scores that actually *have* explicit breaks.
2) Strip away all manual positioning from notes, chords, accidentals, and ties - also any user mirroring - and hope the new defaults render those adjustments unnecessary. We might want to put up a dialog on import (or have a preference setting) to say whether this should be done or not.
But we should do a bit more investigation - checking a representative sample of scores to see what differences actually exist - before deciding on a course of action.