[development] Move all core modules into their own directories.

[drupal]

> I've read your blog post and am particularly interested in trying to  
> test this as soon it is working as intended.  Step #1 is to run the  
> scripts and to do some performance benchmark.  Have you done any  
> experiments yet?  When can we expect to be able to play with this?  :-)
Not really, haven't had time yet. Will do over the weekend. To test there is a need for a 
small change in theme.inc, and that's all.

> Thanks for taking a lead in this, Vlado!  Much appreciated.
Well, Adrian is the one who's pushing :)

As a sidenote - documentation. Is anyone interested in helping me
prepare a theming reference. The reference from the apis is not good for
designers. 

Ultimately I would like to be able to automatically produce the html
snippets, for each theme function, regardless of what is the template
engine. 

My plan is to:

1. catalogue all available theme_ functions in core (for all practical
purposes this is done, might need tweaking, but the code is there)

2. go through the theme_ functions and construct dummy(lorem ipsum)
style calls to extract a formatted html. 

3. look into producing a drupaldocs like description.

This suggestion is closely related to testing as well. How would you
approach it? Any ideas?

Cheers,
Vlado