Update media default design models. 
    
        - Remove sleeve-folder inside and outside design from default
          models. Massive reproduction of sleeve-folder-inside and
          sleeve-folder-outside designs is not as easy as I thought
          previously. 
          
          The massive reproduction of sleeve-folder design is a work we
          would like to face in the future. But until that time comes, I'm
          trying to keep things plain and simple. If I am not going to
          build it, and no one claims for sleeve-folder design to exist,
          don't see a reason to keep it at present time.
    
        - Leave just label-cd and sleeve-cd designs which are easier to
          build. Update deisgns to start using Liberation Serif
          font-family and A4 paper format.