Syncing afterSave/afterDelete trigger calls (Issue #2489) (#2499)

* Implemented syncing afterSave/afterDelete trigger calls with REST request execution flow (Issue 2489). After this change, afterSave and afterDelete triggers CAN return a promise, which needs to be resolved inside a trigger for REST request flow to continue. If trigger doesn't return a promise, request flow continues.

* Added {} to multiline if.

* Fixed bad commit.

* Fixed problem with beforeSave triggers becoming async.

src/rest.js

@@ -86,8 +86,7 @@ function del(config, auth, className, objectId, clientSDK) {
       objectId: objectId
     }, options);
   }).then(() => {
-    triggers.maybeRunTrigger(triggers.Types.afterDelete, auth, inflatedObject, null, config);
-    return;
+    return triggers.maybeRunTrigger(triggers.Types.afterDelete, auth, inflatedObject, null, config);    
   });
 }