[metapost] new MetaPost tutorial to spread

[Clément Hurlin]

Dear users of MetaPost,

  I've written a tutorial to MetaPost and I would be glad if it can be 
diffused on appropriate websites. As the first motivation for this writing 
was the lack of information on MetaPost in other languages than English, I 
wrote in French, Italian (thanks to the help of Mrs Montel) and English.

You can find all three versions on this page:
http://www-sop.inria.fr/everest/personnel/Clement.Hurlin/misc.html

Hope it helps,
Clément Hurlin