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.

Variables xbrushwidth and gridwidth (to be set e.g. in
.spiceinit) allow setting separately the linewidths of the
graph (xbrushwidth) and the grid (gridwidth).

Slight modification of the Windows GUI string window to
enhance readability.

Windows GUI is now more responsive during lengthy op
calculations.