[Squeakfoundation]PackageInfo and refactoring the image

[danielv@netvision.net.il]

I think we should put Avi's newly isolated PackageInfo in the image.
Why? 

It makes the *methodCategory convention for class extensions concrete. 

This would allow tools such as a PackageBrowser that really views all of
a package, and nothing else, Lint over a package, and so forth.

One of the ways to refactor the image is to find and declare all class
extensions (Object>>asString). The new PI can answer questions of the
type - "who references my classes outside myself?", which gives proper
feedback to such refactorings.

BTW, so far, Ned and Andreas have mentioned at some point that they
think PI should be in the image.

What do you guys think?

Daniel