ObjectRepository update

I just checked in an update to ObjectRepository that fixes a bug but 
also changes the way most of the classes within that file are coded to 
prevent a similar bug in the future. I'm pretty sure it all still works 
now but just in case now you know how broke it :).

Here's the comments from my commit:

--- Begin comments ---
saw_092603_1 - Recoded most of the classes within ObjectRepository to 
fix a current bug but more importantly to prevent the same type of bug 
in the future. Specifically the clearState() method was not being 
overridden. The way the classes were coded, they extended from 
ObjectRepository (and therefore DefaultStateMap) but in fact was not 
utilizing anything provided from those classes.
--- End comments ---

You can find additional comments directly in the file tagged with 
saw_092603_1.

While making these changes a question came to mind. What does the 
StateMap interface offer that the java.util.Map interface doesn't? It 
looks like it simply uses an alternate naming convention but only 
includes a handful of the functions. Anyone have a better idea?

Thanks,
-shawn