Added Zotero.DataObjects.sortByParent() to sort child items immediately
after their parent items. Zotero.DataObjects.sortByLevel(), which is
used for collections, sorts each level together, but that's less
appropriate for items where, e.g., an embedded-image attachment should
immediately follow the note that depends on it.
Return false for single ids or skip for multiple ids. This is the original
behavior, but at some point it started throwing an UnloadedDataException. IDs
are always loaded at initialization, though, so we know whether the objects
actually exist.
Replace Z.DataObjects::diff() with Z.DataObjectUtilities.diff(). Instead
of just returning two objects with the differing fields, the new diff()
generates a changeset with operations to apply with applyChanges(),
including at the array member level for collections and tags. This,
combined with cached pristine copies of objects, will allow for vastly
better conflict resolution, with automatic merging of non-conflicting
changes.
Creators currently don't show granular changes, and ordering might make
it too tough to do so. Relations diffing isn't yet implemented.
