Update help.sh:
    
        - Move backend specific definitions from this file to
          `Backends/Texinfo/texinfo.sh' and execute the backend
          functionality.
    
        - Update variable information to coincide with the movement of
          backend specific definitions. The MANUAL_BASEDIR points to
          `trunk/Manuals' and MANUAL_BACKEND the appropriate backend
          inside it. Later, inside the backend specific initialization
          function, the MANUAL_BASEDIR is redefined to refer the place
          where language-specific source files, for the documentation
          backend, are store id.