Also:
- Remove last-sync-time mechanism for both WebDAV and ZFS, since it can
be determined by storage properties (mtime/md5) in data sync
- Add option to include synced storage properties in item toJSON()
instead of local file properties
- Set "Fake-Server-Match" header in setHTTPResponse() test support
function, which can be used for request count assertions -- see
resetRequestCount() and assertRequestCount() in webdavTest.js
- Allow string (e.g., 'to_download') instead of constant in
Zotero.Sync.Data.Local.setSyncState()
- Misc storage tweaks
