Optimize starting with an image as parameter

When starting up and an image was passed, push immediately the image viewer with no animation.

Use a placeholder image delegate for the image viewer to show the desired image before the whole model is done loading, and destroy it after is done

Fetch the title for the page from the passed url before the one form the model is available

Use a placeholder loading hourglass while the model is loading

With all of this, the desired image is shown immediately, even tough navigating to next/prev will be functional only after the model is fully loaded