Out of sync when selecting another image before panorama loaded

[Aerilius]

When browsing quickly over a lot of images (several panoramas), a new panorama request (2) is sent to the WebView before the previous (1) is completed. PhotoSphereViewer throws an error when called while it is still loading a panorama (1).
As a consequence, Eye of Gnome's titlebar shows the current title of (2), while the WebView shows (1).

[Aerilius]

As a workaround, one should wait until a panorama finishes loading before stepping to the next image.

[Aerilius]

• The ideal solution would be if request of (2) immediately aborts loading of (1) and starts loading (2) instead.

• If we let PhotoSphereViewer not refuse request (2), we get concurrency issues (after an image completes loading, the wrong camera parameters are applied; WebView instead of EogScrollView etc.)

• If we queue request (2) to be processed only after (1) completes, it would delay the conflict resolution. What if the active image is then already (3) or (4)?