Plots the input vector used to generate 'wbs' object x with fitted piecewise constant function, equal to the mean
between change-points specified in cpt.
# S3 method for wbs
plot(x, cpt, ...)an object of class 'wbs', returned by wbs
a vector of integers with localisations of change-points
other parameters which may be passed to plot and changepoints
When cpt is omitted, the function automatically finds change-points
using changepoints function with strengthened Schwarz Information Criterion as a stopping criterion for the WBS algorithm.