This function wraps around plot_ss_class_var
to write the ggplot as a vector
format file (*.svg) and return a path to the file that could be used for the
web.
plot_ss_class_var_svg(var, val, g_svg, web_svg, redo = F, ht_ratio = 0.3, ...)
variable to plot, for getting distribution of all Class averages from ss_gl_classes
average value to plot as a vertical line
local file path to output ggplot as scalable vector graphic (*.svg)
web prefix with which to return the path in HTML as an image
ratio of height to width; default = 0.3
other parameters to pass onto plot_ss_class_var