draw_lines(ncfilens, values, varname):
  ncfilens= [filen] ',' separated list of netCDF files
  values= [dimvname]:[valuesaxis]:[dimtit]:[dimxyfmt]:[leglabels]:[vtit]:[title]:[legvals]:[colns]:[lines]
    [points]:[lwdths]:[psizes]:[freqv]:[figname]:[graphk]:[close]
      [dimvname]: ',' list of names of the variable with he values of the common dimension
      [valuesaxis]: which axis will be used for the values ('x', or 'y')
      [dimtit]: title for the common dimension
      [dimxyfmt]=[dxs],[dxf],[Ndx],[ordx],[dys],[dyf],[Ndy],[ordx]: format of the values at each axis (or 'auto')
        [dxs]: style of x-axis ('auto' for 'pretty')
          'Nfix', values computed at even 'Ndx'
          'Vfix', values computed at even 'Ndx' increments
          'pretty', values computed following aprox. 'Ndx' at 'pretty' intervals (2.,2.5,4,5,10)
        [dxf]: format of the labels at the x-axis ('auto' for '%5g')
        [Ndx]: Number of ticks at the x-axis ('auto' for 5)
        [ordx]: angle of orientation of ticks at the x-axis ('auto' for horizontal)
        [dys]: style of y-axis ('auto' for 'pretty')
        [dyf]: format of the labels at the y-axis ('auto' for '%5g')
        [Ndy]: Number of ticks at the y-axis ('auto' for 5)
        [ordy]: angle of orientation of ticks at the y-axis ('auto' for horizontal)
    [leglabels]: ',' separated list of names for the legend ('!' for spaces)
    [vartit]: name of the variable in the graph
    [title]: title of the plot ('|' for spaces)
    [legvals]=[locleg]|[fontsize]:
      [locleg]: location of the legend (0, autmoatic)
        1: 'upper right', 2: 'upper left', 3: 'lower left', 4: 'lower right',
        5: 'right', 6: 'center left', 7: 'center right', 8: 'lower center',
        9: 'upper center', 10: 'center'
      [fontsize]: font size for the legend (auto for 12)
    [colns]= ',' list of color names ('None' for automatic, single value for all the same)
    [lines]= ',' list of style of lines ('None' for automatic, single value for all the same)
    [points]= '@' list of style of points ('None' for automatic, single value for all the same)
    [lwdths]= ',' list of withs of lines ('None' for automatic, single value for all the same)
    [psizes]= ',' list of size of points ('None' for automatic, single value for all the same)
    [freqv]= frequency of values ('all' for all values)
    [figname]= name of the figure
    [graphk]: kind of the graphic
    [close]: should figure be closed (finished)
  varname= variable to plot