[Cuis] Features + Package dependency + new GitHub organization + new packages

[Juan Vuletich]

Hi Folks,

I've just done a first commit to 
https://github.com/Cuis-Smalltalk/Development . This includes the cool 
Features work by Ken Dickey, integrated and tweaked by yours truly. Now 
packages can specify dependence on some Features, optionally including a 
Version or a Version.Revision number. Dependency loading is automatic! 
Just load the package you want (interactively or by Smalltalk code as in 
the Feature class comment), and requirements will be automatically 
loaded in proper order.

This new repo includes all the change sets since the release of Cuis 4.1 
in April. ChangeSet 1749 includes Ken's Features code verbatim. 
Subsequent change sets integrate, and modify it (some subtle bug fixes, 
some style changes, lots of changes for integration). Ken, thanks for 
this important contribution. Please feel free to review my later 
changes, and challenge those you don't agree with. There is more work 
needed to make package dependency work smoothly, especially on 
integration with Package List and other tools...

I also included StyledTextEditor and a new SignalProcessing package with 
stuff from PhotoSqueak, etc. The idea is to include there all packages 
that are currently maintained. To contribute code, please use an image 
with all these packages already loaded, and include new versions of 
affected packages. This will ensure we don't break them while we evolve 
Cuis.

The old repo is now obsolete.

Please test, complain if appropriate, report bugs or annoyances, and if 
possible, enjoy.

Cheers,
Juan Vuletich