Plot Node
A plot node wrapping any PlotIfc implementation.
Renderers decide how to handle the plot based on their output format:
HTML renderers call PlotIfc.toEmbeddedHTML to inline the Lets-Plot fragment
File-based renderers call PlotIfc.saveToFile and embed a reference
Text renderers write the file path as a caption line
Parameters
plot
the plot to render
caption
optional caption displayed below the plot