Guile module system documentation committed

[Martin Grabmueller]

Hello folks,

over the weekend, I have been entertaining myself by reading
boot-9.scm, modules.c and eval.c, trying to figure out how the current
module system works, what's possible with it and what is not.

While going through all the files, I wrote documentation for all (IMO)
important procedures and concepts, and tried to explain everything and
put it into some useful structure.

I have committed it to CVS under the name 

guile-core/devel/modules/module-snippets.texi

and would like some comments, if you can manage to run makeinfo and
going through all this.

- Should we include this in use documentation?

- If yes, what topics have I forgotten/overseen and should add?

- Is the information contained correct?

- Is everything important covered?

If you don't know much about the module sytem, I nevertheless
recommend the lecture, in the hope that it will be as informative to
you as it was to me while writing.

Regards, and happy reading,
  'martin