Prevent empty _events properties from causing an exception.

gistfile1.js

@@ -422,11 +422,16 @@ define('api/sketchfab-iframe',[ "vendors/q/q.min"], function( Q ) {
                 this._events[data.status] = undefined;
             }
         } else {
-            if (this._events[data.status].resolve !== undefined) {
-                this._events[data.status].resolve(data);
-                if (clear) {
-                    this._events[data.status] = undefined;
+            // XXXsecretrobotron: Added an extra `if` layer to protect against unexpected empty `_events` properties.
+            if (this._events[data.status]) {
+                if (this._events[data.status].resolve !== undefined) {
+                    this._events[data.status].resolve(data);
+                    if (clear) {
+                        this._events[data.status] = undefined;
+                    }
                 }
+            } else {
+                console.warn('Unexpected event not handled: "' + data.status + '"');
             }
         }
     };