use utf-8 for encoding of strings, this enables UNICODE
international characters sets (of nearly any language)
in titles, labels, file and folder names.

Windows uses utf-16 and conversion functions between utf-8
and utf-16, if access to Windows API functions is needed.
A special fopen has been defined.

In addition, plot labels on the y axis now are placed
vertically, 90°, by using the Windows API or the Linux Xft library.

Postscript plotting uses only a UNICODE subset, namely
ISO-8859-1/ISO-8859-15, that allows extended ascii.

Better looking fonts are now used for labelling the axes.