Last extra Math Guide section: Technical details

This is now uploaded to the ODF site.

Thank you, Hazel! I will collect them all and work on revising the book.

If you feel like tackling some more translations, I believe there are
things to be done for the Draw Guide. Someone will need to point to
the location of the German files you should use. PeterS will be doing
other Draw Guide updates (for v3.5), so this might be a good time to
incorporate the German updates as well.

--Jean