- Candle plot improvements (Georg Troska):

   * Rearragement of TCandle-code - split into calculate and paint
   * Implementation for a "raw-data candle" inside TCandle - to be used from TTreeViewer in the future
   * Implementation of 1D histograms along each candle (left, right and violin) - to be used for violin-charts
   * Implementation of a zero indicator line for TCandle - to be used for violin-charts
   * Reimplementation if THistPainter draw option VIOLIN
   * Implementations of presets and individual options for VIOLIN-charts
   * Implementation of VIOLIN-charts in THStack - can be combined with CANDLE
   * Update of the docs (THistPainter and THStack)
   * New tutorials