04 Spanish translation, 4th chapter, new address

Hello everyone,

Several things to say today:
1) I've been noticed yesterday that Jorge "Koke" Bernal has translated
the first three chapters of the course in Spanish, so feel free to look
at his page if you speak Spanish:
http://sindominio.net/koke/?s=trans

2) Plus, he has written a "parallel" fourth chapter about mathematical
expressions. This chapter is at the moment only available in Spanish at
http://sindominio.net/koke/?s=docs

That's all folks!

Isa