Update centos-art.sh script.
    
     - When rendering themes, paths like the following doesn't work:
    
           Identity/Themes/Modern/1/Distro/5/Grub
    
       This is because the filter used inside render_setThemesDirStructure
       isn't applying the path. In this commit I made it to apply it.
    
     - The message printed by centos-art.sh script when the theme filter
       doesn't match any directory was also updated to be more accurate
       with its meaning.