Update `texinfo' documentation backend in `help' functionality:
    
        - Start using $PWD variable as base to build the top-level
          directory where documentation manuals will be sotred in.
          Possible locations are restricted to directories under
          `branches/Manuals' and `trunk/Manuals' directories.
    
        - Start using manual directory name as source location to
          syncronize changes from the repository to the working copy. This
          happens just before executing backend's initialization script.
    
        - Update variable names.