Update the render functionality of `centos-art.sh' to accept
    compressed design models as valid templates. 
    
        - Now you can render both `svg' and `svgz' files.
    
        - Use `svgz' files if you can. This is the prefered format from
          now on.
    
        - Using `svgz' design models forbids us from seeing changes inside
          the svg file inside the compressed version. However seeing such
          changes hasn't been too much useful so far. In case you need to
          keep track of such internal SVG changes, don't use `svgz' files.
          Instead, use `svg' files.