A convenience function to export all open figures to graphics file or print them.
printall(root,printoptions) uses root as the root for output filenames
and forms actual names by adding figure number and, if available,
window titles (Characters which might be confusing to the
filesystem are changed.

printall sends all open figures to printer

All options are passed on to PRINT command, except
'-append' - make one file only (only postscript option)

if instead of one of the options a numerical of figure handles
is provided, only print those figures instead of all