Adds the current plot information to plot control list (support function).
setExplan(current, old = NULL)
the current plot information.
existing explanation information.
A list having four components:
a list having two components:
name
component in Plot
cex the size of the text
to write in the explanation
a list having seven components and controlling both lines and points:
a list having two components:
a list like current
with the defaults set
Added from smwrGraphs.