Finished translation and corrected source

[djbasson]

I finished all translation, except possibly in a few places.
I also fixed all places where the source didn't validate or where PreTeXt gave errors when compiling or where LaTeX gave errors when compiling the generated code.

Some things have not been fixed:

• is still in beta, so not yet allowed according to the schema, so places where we embed GeoGebra worksheets give errors upon validation (but not on compilation as far as I know)
• the LaTeX code still gives a few errors, maybe because of a package that is deprecate - don't know if we should contact Rob about this - it only happens in one or two places where we put two images inside a

There are more things I want to do, but I thought the source is now in a good enough place that you can use it to update the notes you host on your webpage. Maybe some decisions can be made over where exactly hints, answers and solutions should be placed, but I don't know how to do that yet.