[Zope] ZDiscussions repackaging

[Dennis Allison]

We have repurposed the ZDiscussion product and now need to repackage it 
so we can easily create instance of our repurposed discussions.  It would 
seem to be a straightforward thing, but it's been causing me difficulty.

What we've done is modify an instance of ZDiscussion to do our bidding.  Having 
gotten a version we like, we want to make it into a ZClass so we can instantiate
instances of the revised ZDiscussion.  And, truth be told, there are several 
different and distinct variations on the theme that we want to work in the same
system.

It should almost be as simple as copying code, but it isn't.  There's an 
inheritence issue--ZItem and ZTopic (the inner classes) both inherit from 
ZBase.  The code for ZBase is nowhere to be seen.  It does appear that the 
ZClass names are hardwired somehowa.

So, the goal is to take variations (significant variations) of ZDiscussions 
instances and refactor them into standalone products.  How to do it?

-dra