[Dev] Attribute Editor API proposal

[Donn Denman]

We're developing Attribute Editors - a set of plug-in classes that 
display and edit attributes based on their type.  We're currently using 
Attribute Editors in Tables and starting to use them in other contexts 
as well.  I wrote up a proposal for an update to the API that we're 
using to allow the Attribute Editors to be easier to write and more 
flexible.  The details are on this wiki page:

http://wiki.osafoundation.org/twiki/bin/view/Chandler/AttributeEditorApi

- Donn Denman