Ugly, ugly hack to enable reversion of docs with unautosaved changes
Autosaved contents take precedent over regular ones
Use -mostRecentlySavedFileURL for DRY
Autosave-elsewhere existing saved docs by going via a temp location
Track and cleanup temp directory upon closing doc
Factor out -deleteAutosavedContentsTempDirectory
Remove temp directory when reverting too
Copy persisten store based on autosave info

Rather than store's knowledge
Document temp directory logic
Delete temp directory after saving too