Typesetting non-ASCII characters with TeX

TeX can typeset an enormous amount of characters. Historically it uses special
TeX commands for individual characters. To directly use Unicode characters
instead, the input encoding package of LaTeX can be used. To tell PyX to
communicate with LaTeX in a certain character encoding differently from the
default ASCII encoding, a `texenc` argument has to be passed to the `text.set`
method as shown in the example for the UTF-8 encoding.
