* output.capture() for update_fig
  * rgrid update did not work:
    problem sees to be in
    self.initialize_plot(ax=self.ax, cax=self.cax, do_infostr=False)
    therefore replaced this by load_hsnap, interp_to_rectgrid, and
    hplot_base

notebooks/examp_pyicon_transports.ipynb: Added example notebooks for barotropic and meridional streamfunctions.