GDP: translating LM 1+2

[Graham Percival]

11 months into GDP, I'm finally comfortable asking the translators
to start.  Translators: please translate the latest versions of
LM 1+2, introduction.itely + tutorial.itely

While you're working, please read the English text carefully --
there might still be typos and whatnot.  I do not expect any
changes to these files other than typo fixes.  Changes are still
possible in every other .itely file, however.

Cheers,
- Graham