Fix issues from code review

src/controls/Controls.Orbit.js

@@ -208,8 +208,7 @@ class Orbit extends EventEmitter {
 
   // Add controls to world instance and store world reference
   addTo(world) {
-    world.addControls(this);
-    return Promise.resolve(this);
+    return world.addControls(this);
   }
 
   // Internal method called by World.addControls to actually add the controls

src/layer/GeoJSONLayer.js

@@ -86,6 +86,8 @@ class GeoJSONLayer extends LayerGroup {
 
         // Clear request reference
         this._request = null;
+
+        reject(err);
       });
     });
   }