compiler wrote
1.- Single quote character (') into a <code z80> environment:
You can't escape here. The code is given to GeSHi for syntax highlighting. If your code is correct syntax (I assume it is) and GeSHi highlights it wrong, it's a bug in GeShi and should reported to its author.
compiler wrote
2.- The "^" character inside a table:
Chi answered that one.
compiler wrote
3.- How to put COMMENTS in the wiki-code, something like:
I think there is a plugin available. There is no syntax to do so out of the box.