Fix unnecessary sync looping after downloading items

An extra sync loop would be performed for every object downloaded, so a
download to an empty database could result in a huge number of
unnecessary loops. This was a regression from 52932b6eb, which started
queuing auto-syncs while a sync was in progress. The fix here is to skip
auto-sync for all objects saved from a sync download.

There are two new mechanisms involved:

- Event-level notifier options that get passed to passed to notify() at
  the top level of extraData rather than being included with every
  object (e.g., because `skipAutoSync` should apply to an entire save
  transaction)
- The ability to pass event-level notifier options when initializing
  a Zotero.Notifier.Queue, such as the one used for sync downloads

test/tests/notifierTest.js

@@ -78,4 +78,38 @@ describe("Zotero.Notifier", function () {
 			assert.isTrue(promise2.isRejected());
 		});
 	});
+	
+	describe("Queue", function () {
+		describe("#commit()", function () {
+			it("should add options from queue to extraData", async function () {
+				var called = false;
+				var data;
+				
+				var notifierID = Zotero.Notifier.registerObserver({
+					notify: (event, type, ids, extraData) => {
+						called = true;
+						data = extraData;
+					}
+				});
+				
+				var notifierQueue = new Zotero.Notifier.Queue({
+					skipAutoSync: true
+				});
+				
+				var item = createUnsavedDataObject('item');
+				await item.saveTx({
+					notifierQueue
+				});
+				
+				assert.isFalse(called);
+				
+				await Zotero.Notifier.commit(notifierQueue);
+				
+				assert.isTrue(called);
+				assert.propertyVal(data, 'skipAutoSync', true);
+				
+				Zotero.Notifier.unregisterObserver(notifierID);
+			});
+		});
+	});
 });