Add supporting 2D mode

Author: Takayuki MATSUOKA

Assets/SceneViewFovControl/Editor/Status.cs

@@ -15,6 +15,10 @@ public void OnScene(SceneView sceneView) {
             return;
         }
 
+        if(sceneView.in2DMode) {
+            return;
+        }
+
         Camera camera = sceneView.camera;
         if(fov == 0.0f) {
             fov = camera.fieldOfView;