[Cuis] Cuis base image reduced by 25%!

[Juan Vuletich]

Hi Folks,

A few days ago I started playing with the idea of extracting 
non-essential functionality into .pck.st files. The result is that I 
could reduce Cuis by about 25%. Now it is below 500 classes and below 
100kLOC :) . The new packages are:

- Compression
- Graphic-Files-Additional (only png and tiff, as bmp and jpg are in the 
base image)
- Sound
- Theme-Themes (Only the default class Theme is included in the base image)
- Network-Kernel
- LinearAlgebra
- Test

If you update your image, all this code will be removed. If you download 
the updated image, it is no longer there. The packages themselves are 
also available at github, together with a txt file with a possible load 
order. I hope you'll find this more convenient when contributing code.

There are several open questions, and I ask for your opinions and thoughts.

1) The "official" Cuis image can have none/some/all of these preloaded. 
We need to allow for clean unload of packages, but if there are no 
overrides, I think it is not a big deal. I'm not sure what's best. Maybe 
all these packages (and maybe others) should be preloaded by default.

2) I'm starting to believe that it is best to have those packages that 
are kept up to date in the same git repo as the base image. This will 
make it very easy to know what is the proper snapshot of some package to 
be used with a particular Cuis update level. Besides, it makes sense to 
have a Cuis-Smalltalk organization. Therefore I created 
https://github.com/Cuis-Smalltalk , although I haven't saved anything 
there yet. I'd like to discuss with you the repositories to keep and 
their structure. I think that we might store there those packages that 
are preloaded, and those that are well maintained and actually used. But 
on the other hand, folks wanting to have better control of their code 
might prefer to host them in their own repositories...

After all this, https://github.com/jvuletich/Cuis should be deleted or 
marked as historic.

BTW, there are a few other fixes and enhancements in this last batch of 
updates. #reduceCuis now produces a 3.6Mb image with less than 80kLOC. 
Another tweak was to no longer kill the active changeset on image save. 
I hope this fits people who usually save the dev image at the end of the 
day.

Let's discuss and think of better ways to manage the Cuis codebase.

Cheers,
Juan Vuletich