anchor.diff:    /// respectively.
     ///
     /// [category:Grouping, windowing and chunking]
  -  [<Obsolete("The Frame.UnStack method has been renamed to Frame.Pivot")>]
  +  [<Obsolete("The Frame.UnStack method has been renamed to Frame.Unmelt")>]
     [<CompiledName("UnStack")>]
  -  let unstack (frame:Frame<'O, string>) : Frame<'R, 'C> = pivot frame
  +  let unstack (frame:Frame<'O, string>) : Frame<'R, 'C> = unmelt frame
   
     // ----------------------------------------------------------------------------------------------
     // Sorting and index manipulation
  
positive.code:   /// respectively.
    ///
    /// [category:Grouping, windowing and chunking]
    [<CompiledName("Pivot")>]
    let pivot (frame:Frame<'O, string>) : Frame<'R, 'C> =
      FrameUtils.fromValues frame.Rows.Values 
        (fun row -> row.GetAs<'C>("Column"))
        (fun row -> row.GetAs<'R>("Row"))
  
negative.code: /// `pivotTable` implements the pivoting operation [as documented in the 
  /// tutorials](../frame.html#pivot).
  ///
  /// The `melt` and `unmelt` functions turn the data frame into a single data frame
  /// containing columns `Row`, `Column` and `Value` containing the data of the original
  /// frame; `melt` can be used to turn this representation back into an original frame.
  ///
  