Remove version number from final png files. 
    
        - Previous to this commit final files used the schema:
          resolution-final-releasever.png. This schema is not supported
          anymore for the following reasons:
    
            Using release numbers for final files (e.g.,
            800x600-final-1.png, 800x600-final-2.png, etc.) makes
            difficult to link the last background from areas. We would
            need to be aware of the last numerical release to change it in
            those areas who use them, and this is not desired since we are
            trying to automate art works production as much as possible.
            
            Instead, consider using just one final file (e.g.,
            800x600-final.png) which will be updated with the last
            information. 
            
            If you want to test new art works, you can add the release
            number as prefix after 'final' (e.g., 800x600-final-1.png,
            800x600-final-2.png, etc.) and when you consider it ready for
            using, rename the old final art work with your new one. 
            
            With this schema, there is no need to change background
            information in other areas that use them in order to use the
            last work. Propagation of last art work, in other areas that
            use theme backgrounds (i.e., all theme sections), is
            controlled by the action of updating one unique final.png
            background file for each screen resolution available.
    
            Resuming: Use the resolution-final.png schema whenever you
            want to create final background images. For exmaple, if you
            want to create the final work for 800x600.png file, use the
            file name 800x600-final.png.