ENH: Implement a few plotters for plotting nodes
ENH: Implement a few plotters for plotting nodes

Plotter classes can be used to create callable objects which can be
given as plotting functions when creating nodes. Three plotters have
been implemented now:
  GaussianMarkovChainPlotter
  GaussianTimeseriesPlotter
  GaussianHintonPlotter
When constructing the plotter, you can give keyword arguments which are
passed to the corresponding plotting function.

SalemAmeen/bayespy,bayespy/bayespy,fivejjs/bayespy,jluttine/bayespy