Added minimal UTF-8 support

In addition to the ASCII characters add support for:
- various accented characters
- other letters needed for writing languages of Western Europe
- some special characters

Change-Id: I72cc1fd1517c5b1aed6a0021dec0174928886dac
Reviewed-on: https://iffwww.iff.kfa-juelich.de/review/124
Reviewed-by: Christian Felder <c.felder@fz-juelich.de>
Reviewed-by: Josef Heinen <j.heinen@fz-juelich.de>