More gracefully handle recoverable save errors

Big thanks to @adib for helping me hunt this one down
correct typo
Try shifting -performActivity:… a little earlier
Otherwise doing two saves very close together will attempt the second one before the first has cleared out ivars
Trouble is it clears ivars too soon when autosaving now!
Only do activity-based logic if there's a recoverable error
Merge branch 'ksmanageddocument' into duplicate-sqlite-stores

Conflicts:
	BSManagedDocument.m