combine multiple pdf files into a single multipage pdf file.
pdfconcat(outfile, infiles, verb)
a string, name of the output file.
an array of strings, names of the input files.
a boolean
pdfconcat
combine multiple pdf files in a single multipage pdf file. If verb is equal to %t then
statistics of each input file are displayed on the command line. Note that outfile cannot be an element of infiles.