DataSetSection_multivars(values, filen, varn)
  values= [varn1],[beg1],[end1],[int1]@[...[[varnM],[begM],[endM],[intM]]]
    [varni]: name of the variable with exception of:
      'dist;[var1],[val1]|[...,[varN],val2]] distance computed from sqrt[sum_i([vari]-[vali])^2)]
        variables have to be of the same shape and share dimensions
    [begi],[endi],[inti]: beginning, end and interval along the variable
      [endi] = -1, maximum value
      [inti] = -1, all the values within the range (default)
        = 0, single value. [begi] will be taken as the reference value
        NOTE: variables without section by the variables are taken allover their size
        NOTE2: if inti = 'str', it is assumed that the variable is a string-list of values
          then [begi] must be the string to be used for the search ('!', for spaces)
  filen= netCDF with the data-set
  varn= ',' list of variables ('all', for all variables)