New FullScreenView class

[Marcel Wiesweg]

looking forward to it!


> The current full screen view based on the slideshow is not really good. It
> is not possible to view the image in original size or to zoom the image.
> Although we have another full screen mode, if we also disable the sidebars,
> but somehow it is not as comforable as in Gwenview. In any case, the
> full-screen mode is a criticized point to digiKam in many forums. I will
> continue to develop the patch and provide it for testing. Then we can still
> decide.