Plot different graphs at once

Plot different graphs from an array of plotdata.

For analysing measurements (or simulations) it is often necessary to plot different graphs from an array of data. Some graphs have one line, other have more.

PLOTMAT is a function to do this. Given an array of data, and an array for which columns have to be plotted in which graphs, the graphs are plotted.

There are some possibilities for the x-data to be used.